Main | Family List (MO) | Family List (INBio) | Cutting Edge Draft Treatments | Guidelines | Checklist | Citing | Editors Draft Treatments ARACEAE By M. H. Grayum English, final draft: placed 1/May/2000 Philodendron Croat, T. B. 1997. A revision of Philodendron subgenus Philodendron (Araceae) for Mexico and Central America. Ann. Missouri Bot. Gard. 84: 311-704. Grayum, M. H. 1996. Revision of Philodendron subgenus Pteromischum (Araceae) for Pacific and Caribbean tropical America. Syst. Bot. Monogr. 47: 1-233. Ca. 500-700 spp., throughout trop. and subtrop. regions of New World; 62 spp. in CR. Terrestrial, or (more commonly) appressed-climbing hemiepiphytes to canopy vines or (infrequently) true epiphytes; stems brief (rarely obsolete) to greatly elongate; plants glabrous to (rarely) squamiferous, without milky sap (sap rarely becoming whitish after exposure to air). Leaves spiraled. Petioles very rarely (elsewhere) peltately attached, not (or weakly) geniculate. Leaf-blades simple or (much less commonly) compound (trifoliolate or very rarely pedately compound), when simple narrowly lanceolate to ovate-cordate, sagittate, trilobed or pinnately or bipinnately lobed. Infls. 1-numerous per axil, secreting resin at anthesis (from spathe or spadix); spathe with basal tube and distal lamina; spadix with separate male and female regions, with medial sterile zone, with or (usually) without distal sterile appendage. Fls. unisexual, naked; male fls. with 2-6 distinct, prismatic stamens; female fls. usually without conspicuous style; stigma convex, sometimes lobed; ovary (2 or 3)4-6(7-47)-locular; ovules (1-)4-numerous per locule, borne on axile placentae. Frs. usually white or orange, 1-numerous-seeded. Philodendron, the second most sp.-rich genus in Araceae, comprises generally epiphytic plants with clear or resinous (non-milky) sap, simple leaf-blades, ± persistent spathes enveloping the spadix, and naked, unisexual fls. Only three CR spp. (P. grandipes, P. strictum, and P. thalassicum) are characteristically terrestrial, and just four (P. anisotomum, P. cotobrusense, P. rothschuhianum, and P. tripartitum) have compound (trifoliolate) leaf-blades; P. cretosum alone has whitish sap. The CR Araceae genera most likely to be confused with Philodendron are Dieffenbachia, Homalomena, Montrichardia, and Zantedeschia, all of which are strictly terrestrial; see under those genera for additional distinguishing features. Those Philodendron spp. with trifoliolate leaf-blades (see above) are often misidentified as Syngonium, but spp. of the latter genus virtually always yield copious milky sap. Philodendron radiatum (which see) is frequently taken for a Monstera sp. because of its large, deeply divided leaf-blades. Several native as well as exotic Philodendron spp. are occasionally cult. as ornamentals in CR. The most conspicuous of the exotic spp. is P. bipinnatifidum Schott ex Endl. [incl. P. selloum K. Koch; Grayum 9682 (MO)], of the South Amer. subg. Meconostigma. This sp. is recognized by its stout, conspicuously leaf-scarred trunks and very large, bipinnately lobed leaf-blades similar to those of P. radiatum. Among the native spp., P. anisotomum, P. auriculatum, P. brenesii, P. davidsonii, P. hederaceum, and P. wendlandii are favorite horticultural subjects. 1 Stems of mature (flowering) plants lacking cataphylls, though cataphylls sometimes present among the infls.; petioles of all leaves narrowly amplexicaul, sheathed > halfway to base of blade (subg. Pteromischum). 2 Appressed-climbing trunk epiphytes, unbranched or very sparingly branched; stems drying yellowish sulcate or green and finely striate; infls. usually borne close to supporting trunk, 1 or 2 per axil, usually subtended by cataphylls; peduncles > 3 cm (or else stems drying green) (sect. Pteromischum). 3 Unsheathed distal portion of petiole virtually always < 1 cm; seeds semicochleate to cochleate. 4 Petiole sheath broadly splayed (at least in distal half), the petioles appearing "winged"; stems drying yellowish brown and coarsely sulcate; adaxial surface of leaf-blade rarely drying granular, usually densely and minutely alveolate; 0-1000 m, widespread...P. sulcatum 4 Petiole sheath involute or erect to ± spreading distally, the petioles rarely appearing "winged"; stems drying green and finely striate; adaxial surface of leaf-blade usually drying granular, rarely subalveolate; 0-700 m, Atl. slope. 5 Petioles > 12.5 cm; leaf-blade > 25 cm, > 4× longer than wide, with < 9 primary lateral veins per side (these usually very obscure); infls. often paired and subtended by cataphylls...P. ensifolium 5 Petioles < 12.5 cm; leaf-blades < 25 cm, < 4× longer than wide, with > 8 primary lateral veins per side; infls. usually solitary and without cataphylls...P. herbaceum 3 Unsheathed distal portion of petiole > 1 cm long (on at least some larger leaves); seeds straight to slightly curved or (P. rhodoaxis) cochleate. 6 Stems persistently green, drying green and finely striate; petioles < 70% of blade length; leaf-blade strongly inequilateral (widest side ca. 56-69% of total width), usually widest above the middle, the largest blades with > 15 primary lateral veins per side; seeds C-shaped to cochleate...P. rhodoaxis 6 Stems becoming yellowish brown, drying coarsely sulcate; petioles > 70% of blade length; leaf-blades weakly to moderately inequilateral (widest side usually ca. 51-58% of total width), usually widest at or below the middle, usually with 15 or fewer primary lateral veins per side; seeds straight to slightly curved. 7 Leaf-blades usually matte to velvety above, with 5-9 primary lateral veins per side; adaxial surface of leaf-blade drying minutely and uniformly alveolate; 0-550 m...P. opacum 7 Leaf-blades usually weakly glossy to glossy above, with (5-)8-15(-21) primary lateral veins per side; adaxial surface of leaf-blade drying smooth to granular, never uniformly alveolate; 0-1750 m. 8 Petiole sheathed for < 3/4 its total length; unsheathed portion of petiole > 6 cm long; 0-600 m, Pac. slope...P. popenoei 8 Petiole sheathed for > 3/4 its total length; unsheathed portion of petiole < 6 cm long; 700-1750 m, both slopes...P. standleyi 2 Loosely scandent, much branched epiphytes; stems drying yellowish brown to blackish and ± coarsely sulcate, never green and finely striate; infls. typically held away from supporting trunk on divergent branches, 1 per axil (1 or 2+ in P. inaequilaterum or, rarely, some other sp.), rarely subtended by cataphylls (except P. inaequilaterum and P. rayanum); peduncles usually < 3 cm long (sect. Fruticosa). 9 Petioles of all leaves with sheaths broadly splayed, the petioles appearing "winged". 10 Petioles of most larger leaves > 10 cm, > 1/2 as long as blade. 11 Unsheathed portion of petiole of larger leaves obsolete to ca. 0.7 cm; leaf-blade narrowly cuneate to rounded or subcordate (the sinus to ca. 0.2 cm deep) at base, with 5-11 primary lateral veins per side; seeds 0.5-1.3 mm; 0-1650 m, widespread and common...P. aurantiifolium 11 Unsheathed portion of petiole of larger leaves ca. 0.5-1.4+ cm; leaf-blade broadly cuneate to rounded or subcordate (the sinus to ca. 0.7 cm deep) at base, with 9-15(-17+) primary lateral veins per side; seeds (1.4-)1.6-1.8 mm; 1450 m, Pac. slope Cerro de la Muerte, very rare...P. rojasianum 10 Petioles of most larger leaves < 10 cm, < 1/2 as long as blade. 12 Petioles (4.9-)5.2-10.4 cm; leaf-blades drying greenish, minutely alveolate on both surfaces (often also granular); spadix at anthesis 8.6-13.6 cm, the female portion ca. 1/5-1/4 the total length; 0-250(-850) m, Pac. slope...P. burgeri 12 Petioles 3.5-7.6 cm; leaf-blades drying brownish, smooth to densely granular (not alveolate) on both surfaces; spadix at anthesis ca. (6.1-)7-9 cm, the female portion ca. 1/4-1/2 the total length; 200-1100 m, both slopes...P. tuerckheimii 9 Petioles of most leaves with sheaths erect to involute (occasionally splayed on leaves subtending infls.), the petioles not appearing "winged". 13 Free, distal portion of petiole sheath ca. 0.7-2.3 cm; leaf-blades coriaceous, with 5-8(9) primary lateral veins per side; spadix at anthesis ca. 15.6-24.6 cm; canopy vines...P. rigidifolium 13 Free, distal portion of petiole sheath obsolete to ca. 1.1 cm; leaf-blades chartaceous or thinly coriaceous to subcoriaceous, with (6-)8-22 primary lateral veins per side; spadix at anthesis ca. 5.8-18.1 cm; understory or subcanopy vines. 14 Largest leaf-blades usually > 15 cm wide and < 3× longer than wide, usually drying blackish; surface of leaf-blade with prominulous tertiary veins enclosing granular areolae; infls. often 2(3) per axil, subtended by reddish, quickly deciduous cataphylls; spadix at anthesis ca. 10-18 cm, the female portion ca. 14-28% of the total length; ripe frs. bright orange...P. inaequilaterum 14 Largest leaf-blades usually < 15 cm wide and > 3× longer than wide, usually drying green or reddish brown; adaxial surface of leaf-blade with tertiary veins obscure to evident, not prominulous and enclosing granular areolae (except P. rayanum); infls. usually solitary, rarely paired, without cataphylls (except P. rayanum); spadix at anthesis ca. 5.9-12.5(-13.7) cm, the female portion ca. 24-37% of the total length; ripe frs. whitish to pale orange. 15 Free, distal portion of petiole sheath to ca. 11 mm; leaf-blade drying with abundant and conspicuous brownish, interrupted resin ducts between secondary lateral veins, these most evident on abaxial surface; external surface of spathe drying with finely parallel, brown resin ducts; fertile male portion of spadix 0.6-1.9 cm wide, the sterile male zone even wider, conspicuously expanded...P. schottii 15 Free, distal portion of petiole sheath to ca. 2.5 mm; leaf-blade drying with resin ducts obscure, or else few and ± continuous; external surface of spathe not conspicuously resinous-striate; fertile male portion of spadix 0.6-1.2 cm wide, the sterile male zone not conspicuously wider. 16 Unsheathed portion of petiole obsolete or to ca. 0.3(-0.5) cm; leaf-blades drying reddish brown, markedly inequilateral (the widest side > 57% of the total width); adaxial surface of leaf-blade drying smooth to moderately granular, the tertiary veins not conspicuous; infls. never subtended by cataphylls...P. alliodorum 16 Unsheathed portion of petiole ca. 0.4-2.5 cm; leaf-blades drying greenish, somewhat inequilateral (the widest side ca. 51-57% of the total width); adaxial surface of leaf-blade with prominulous tertiary veins enclosing granular areolate; infls. regularly subtended by reddish, deciduous cataphylls...P. rayanum 1 Stems of mature plants with foliage leaves regularly alternating with cataphylls, the latter sometimes quickly deciduous, or weathering to fibers; petioles of all leaves attached flush with stem (not amplexicaul), sheathed < halfway to base of blade (subg. Philodendron). 17 Leaf-blades deeply divided pinnately or (especially toward base) bipinnately into narrow lobes...P. radiatum 17 Leaf-blades simple and entire, or trilobate or -foliolate, not pinnately divided (except by tearing, in P. findens). 18 Leaf-blades trilobate to trifoliolate, the lateral lobes directed laterally or slightly backward (i.e., the leaf-blade hastate at base) to forward, longer than wide. 19 Cataphylls persistent, weathering to reddish brown fibers; spathe tube deep reddish or purplish internally and externally; spadix ca. 6-9.9 cm long...P. tenue 19 Cataphylls deciduous intact; spathe tube greenish to reddish or purplish internally, mostly green externally; spadix 7-16.5 cm long. 20 Leaf-blades with main vein of lateral lobes directed slightly backward to laterally; petioles markedly spongy; spadix ca. 15-16 cm long; rare, 30-700 m...P. angustilobum 20 Leaf-blades with main vein of lateral lobes curving weakly to strongly forward; petioles firm to weakly spongy; spadix ca. 7-16.5 cm long; common, 0-1800+ m. 21 Spathe tube uniformly greenish within; 0-900(-1450) m, mainly Atl. slope...P. rothschuhianum 21 Spathe tube pink to reddish or purplish within; 0-1800 m, both slopes. 22 Medial lobe of leaf-blades with 2-5(-7) primary lateral veins per side; spadix usually shorter than peduncle; ripe frs. bright orange; (600-)800-1800+ m...P. anisotomum 22 Medial lobe of leaf-blades with 5-22 primary lateral veins per side; spadix usually longer than peduncle; ripe frs. whitish (unknown in P. cotobrusense); 0-1500+ m. 23 Medial lobe of leaf-blades with ca. 20-22 primary lateral veins per side; infls. to at least 5 per axil; 1250 m, vic. Las Alturas de Coto Brus...P. cotobrusense 23 Medial lobe of leaf-blades with ca. 5-17 primary lateral veins per side; infls. 1 or 2(3?) per axil; 0-1500+ m, both slopes...P. tripartitum 18 Leaf-blades unlobed to cordately, sagittately or subhastately lobed, the lobes directed backward (if only slightly so, then ± as long as wide). 24 Petioles, peduncles, and exterior spathe surface densely covered with fleshy, hairlike scales to ca. 5-10 mm long. 25 Leaf-blades with ca. 7-14 primary lateral veins per side; spadix ca. 0.7-1.2 cm wide; rare, 450-750 m, Atl. slope Volcán Barva...P. squamicaule 25 Leaf-blades with ca. 5-8 primary lateral veins per side; spadix ca. 0.9-1.8 cm wide; common, 200-1500 m, widespread...P. verrucosum 24 Petioles, peduncles, and exterior spathe surface glabrous. 26 Cataphylls weathering to whitish, reddish or brownish fibers, these sometimes forming a reticulum. 27 Leaf-blades attenuate or cuneate to cordulate at base; spathe tube uniformly greenish within. 28 Petioles 9.5-21 cm long; leaf-blades (4.6-)6.4-13.1 cm wide, narrowly oblong or elliptical to oblanceolate, attenuate to cuneate at base; peduncles ca. 3.3-6 cm long; spadix ca. 7.5-11 cm long; sap becoming whitish upon exposure to air...P. cretosum 28 Petioles ca. 34-62 cm long; leaf-blades ca. 17-34 cm wide, ovate to lance-ovate, cordulate at base; peduncles ca. 16-21 cm long; spadix ca. 10.5-14.5 cm long; sap not becoming whitish...P. scalarinerve 27 Leaf-blades prominently cordate to subhastate at base; spathe tube greenish or reddish within. 29 Petioles prominently narrow-winged for most of their length. 30 Petiole wings plane for most of their length, becoming crispate-undulate distally; leaf-blades ca. (25-)34-70 × (18-)28-65 cm, soon tearing pinnately between all primary lateral veins, drying blackish; spathe tube green externally; 100-1400 m, Atl. slope...P. findens 30 Petiole wings undulate for most of their length; leaf-blades ca. 45-115 × 34-86 cm, not regularly tearing, drying greenish; spathe tube reddish to purplish externally; 0-300(-700) m, both slopes...P. pterotum 29 Petioles terete to D-shaped, the margins rounded to acute (but not winged). 31 Plants terrestrial, the stems decumbent to erect, rarely inclining on trunk bases. 32 Leaf-blades ca. 22-46 × 19-38 cm, semiglossy and somewhat paler below; spathe tube greenish or reddish within; 0-700(-1200) m...P. grandipes 32 Leaf-blades ca. 38-77 × 22.5-52 cm, usually matte and much paler (appearing glaucous) below; spathe tube always uniformly greenish within; 1000-2100 m...P. thalassicum 31 Plants appressed-climbing trunk epiphytes, occasionally fallen on ground. 33 Spathe tube uniformly greenish within; ripe frs. white or whitish. 34 Petioles ca. 22-69 cm long; leaf-blades ca. 26-68 × 11.5-34 cm, semiglossy and somewhat paler below; peduncles 3-10.5 cm long; spadix 7.5-10 cm long; 0-1200+ m...P. jodavisianum 34 Petioles ca. 40.5-109 cm long; leaf-blades ca. 38-77 × 22.5-52 cm, matte and much paler (appearing glaucous) below; peduncles ca. 3.5-16 cm long; spadix 7.2-18.4 cm long; 1000-2100 m...P. thalassicum 33 Spathe tube deep reddish within, and often externally as well; ripe frs. white or red. 35 Petioles D-shaped in section, the margins obtuse to acute; leaf-blades 21-52 × 15-38 cm, with ca. 5-7 primary lateral veins per side; ripe frs. red; 0-300+ m, Atl. slope and Golfo Dulce region...P. fragrantissimum 35 Petioles terete or subterete, the margins rounded to obtuse; leaf-blades 32-106 × 15-70 cm, with 6-20 primary lateral veins per side; ripe frs. whitish. 36 Leaf-blades 15-48 cm wide, lance-ovate, lance-deltate, pandurate, or oblong-lanceolate, with ca. 10-20 primary lateral veins per side; spadix ca. 6-9.9 × 0.7-1.2 cm; 0-800(-1000) m, Atl. slope and Golfo Dulce region...P. tenue 36 Leaf-blades ca. 22-70 cm wide, broadly to ± narrowly ovate or oblong, with 6-11 primary lateral veins per side; spadix ca. 7-16.7 × 1.2-2.7 cm; 300-2500 m, both slopes. 37 Peduncles ca. 9-14.5(-17.5) cm long; spathe tube usually reddish externally; spadix 11.5-16.7 cm long; 300-1200 m, Atl. slope and Fila Costeña...P. dodsonii 37 Peduncles ca. 2.5-9(-11) cm long; spathe tube usually mostly green externally; spadix ca. 7-13.7 cm long; 750-2500 m, Atl. slope and near Continental Divide. 38 Petioles ca. 35-51+ cm long; spadix ca. 7-11 × 1.2-2 cm; 2300-2500 m...P. alticola 38 Petioles ca. (48-)63-80+ cm long; spadix ca. 9.4-13.7 × 1.3-2.7 cm; 750-2100 m...P. schottianum 26 Cataphylls deciduous intact, sometimes subpersistent, occasionally deliquescing in situ, sometimes leaving a few basal fibers (but not weathering to a conspicuous fibrous mass). 39 Petioles strongly flattened in dorsiventral plane, ± ribbon-like; loosely climbing epiphytic vines with long internodes and usually ovate-cordate leaf-blades; 0-800(-1050?) m, Atl. slope and Golfo Dulce region...P. platypetiolatum 39 Petioles terete or subterete to D-shaped, not ribbon-like; habit and distribution various. 40 Leaf-blades cuneate to rounded, truncate, auriculate, or subcordate at base. 41 Petiole and leaf-blade midrib very thick and markedly spongy. 42 Appressed-climbing or loosely scandent vines; internodes long; petioles 7-15.5(-26) cm long; leaf-blades ca. 25-37(-55) cm long, with ca. 8-13 primary lateral veins per side; spadix ca. 9.7-12.5 × 0.6-1.2 cm; 0-650 m, Atl. slope...P. ligulatum 42' Appressed-climbing trunk epiphytes to rosette-forming canopy epiphytes; internodes very condensed; petioles 10-49 cm long; leaf-blades ca. 32-75 cm long, with 11-27 primary lateral veins per side; spadix ca. 11-20 × 0.9-1.6 cm; 0-1000(-1250) m, both slopes. 43 Stem short, but ± creeping or decumbent, the leaves not forming a rosette; petioles 17-49 cm long, terete; 0-1000 m, Pac. slope...P. auriculatum 43 Stem very condensed, the leaves forming a rosette; petioles ca. 10-25 cm long, D-shaped in section, the margins acute; 0-700(-1250) m, Atl. slope...P. wendlandii 41 Petiole and leaf-blade midrib firm to moderately compressible, not markedly thickened and spongy. 44 Leaf-blades with primary lateral veins obscure to scarcely visible...[Proceed to couplet 51.] 44 Leaf-blades with primary lateral veins always clearly visible. 45 Leaf-blades with 10-25 primary lateral veins per side; spadix 11.5-19.5 × 1-1.8 cm...[Proceed to couplet 55.] 45 Leaf-blades with 4-11 primary lateral veins per side; spadix 6.5-13.7 × 0.7-1.1(-1.2) cm. 46 Petioles 7-7.3 cm long; leaf-blades 11.5-11.9 cm long, ovate; 1000 m, Valle de El General...P. chirripoense 46 Petioles 4-65.5 cm long; leaf-blades 13.7-63.5 cm long, variously shaped; 0-1400 m, both slopes. 47 Loosely scandent vines; petioles 4-12 cm long; leaf-blades 13.7-26 × 4.5-10.4 cm, with 4-7 primary lateral veins per side; infls. solitary in axils; spadix ca. 6.5-8.7 cm long; 0-1000 m, Atl. slope...P. bakeri 47 Usually appressed-climbing trunk epiphytes; petioles 14-65.5 cm long; leaf-blades ca. 24.5-63.5 × 9-32.5 cm, with (5)6-11 primary lateral veins per side; infls. 1-4 per axil; spadix ca. 8-13.7 cm long; 0-1400 m, both slopes...P. sagittifolium 40 Leaf-blades prominently cordately to sagittately or subhastately lobed at base. 48 Epidermis of stems ± densely and uniformly scabrous or asperous, ultimately exfoliating. 49 Leaves evergreen, the blades with 5-8 primary lateral veins per side; peduncles ca. 2.1-7.5 cm long; spathe tube uniformly greenish within; spadix ca. 6.4-9.5 cm long, the pistils truncate; 0-110 m, Atl. slope...P. brevispathum 49 Leaves deciduous in dry season, the blades with 3-6 primary lateral veins per side; peduncles ca. 5-12 cm long; spathe tube red or purplish within; spadix ca. 9-12.5 cm long, the pistils prolonged distally at anthesis; 0-800 m, Pac. slope (very rare on Atl. slope)...P. jacquinii 48 Epidermis of stems glabrous (sometimes locally pustulate), occasionally (P. brunneicaule) exfoliating. 50 Primary lateral leaf veins obcure or scarcely visible. 51 Leaf-blades > 2× as long as wide, sagittate at base; peduncles ca. 2-4.5 cm; 1200 m, Pac. slope (Tarrazú region)...P. knappiae 51 Leaf-blades < 2× as long as wide, subcordate to cordate at base; 0-500 m, both slopes. 52 Leaf-blades 9.3-21.5 cm wide, reniform to broadly ovate; infls. solitary in axils; peduncles ca. 13-24 cm long; spadix 7.5-13.7 × 0.4-1 cm; 0-500 m, Pac. slope...P. microstictum 52 Leaf-blades 5.5-15.5 cm wide, broadly ovate or deltate to oblong-lanceolate; infls. 1-5 per axil; peduncles ca. 4-10 cm long; spadix ca. 4.4-8.2 × 0.2-0.5 cm; 100-250 m, Atl. slope...P. sulcicaule 50 Primary lateral leaf veins always clearly visible. 53 Leaf-blades lance-ovate to lanceolate or oblong-lanceolate, usually ca. 2× as long as wide, with ca. 10-25 primary lateral veins per side; midrib usually paler than surface above. 54 Leaf-blades matte and glaucous (whitish) below; 800-2200 m, Atl. slope and near Continental Divide...P. brenesii 54 Leaf-blades matte to semiglossy below, not glaucous or whitish. 55 Short-stemmed canopy epiphytes; petioles ca. 48.5-86.5 cm long, D-shaped in section, the margins obtuse to subacute; leaf-blades ca. 41.5-77 × 18-43 cm, with 15-25 primary lateral veins per side; 0-100 m...P. davidsonii 55 Long-stemmed trunk epiphytes; petioles ca. 25-53 cm long, subterete, the margins rounded to obtuse; leaf-blades 27-51 × 9-26 cm, with 10-17 primary lateral veins per side; 750-1300 m...P. lentii 53 Leaf-blades variously shaped, < or > 2× as long as wide, with 2-12 primary lateral veins per side; midrib paler than surface above or not. 56 Thick-stemmed terrestrial plants or appressed-climbing trunk epiphytes, the larger leaf-blades > 30 cm wide, ± broadly ovate to oblong-ovate. 57 Spathe uniformly green; ovaries with 1 ovule per locule; very rare, 1000 m, Pac. slope (Fila Costeña)...P. dominicalense 57 Spathe reddish within tube, sometimes also elsewhere; ovaries with 2-28 ovules per locule; widespread. 58 Plants terrestrial or occasionally appressed-climbing on trunks; cataphylls usually leaving a few basal fibers; petioles finely transversely fissured (especially distally), drying yellowish brown; leaf-blades matte and whitish below; 650-1275 m, Atl. slope and Fila Costeña...P. strictum 58 Plants appressed-climbing trunk epiphytes (though occasionally rooted in ground); cataphylls cleanly deciduous, deliquescent, or leaving a few fibers; petioles not transversely fissured, drying green to brownish; leaf-blades weakly glossy to glossy below, not whitish; 0-2500 m, widespread. 59 Plants usually rooted in ground; internodes on fertile stems to at least 10-15 cm long, with reddish brown, exfoliating epidermis; leaf-blades ± thinly coriaceous, drying reddish brown; infls. solitary in axils; 50-950 m, Atl. slope...P. brunneicaule 59 Plants not rooted in ground; internodes on fertile stems < 10 cm long, with grayish to tan epidermis not easily exfoliating in life; leaf-blades subcoriaceous to coriaceous, drying grayish to brownish or green; infls. 1-5 per axil; 0-2500 m, widespread. 60 Cataphylls usually leaving some fibers; spadix 7-11 × 1.2-2 cm; 2300-2500 m...P. alticola 60 Cataphylls deciduous intact, or leaving some basal fibers; spadix > 11 cm long, or < 1.2 cm wide; 0-1400 m. 61 Petioles < 70 cm long; leaf-blades < 65 cm long and < 35 cm wide; spadix 8-13.7 × 0.7-1(-1.2) cm...P. sagittifolium 61 Petioles to > 70 cm long; leaf-blades to > 65 cm long and > 35 cm wide; spadix 11.5-18 × 1.1-2.3 cm. 62 Peduncles ca. 9-14.5(-17.5) cm long; spathe tube reddish within and externally as well; spadix ca. 11.5-16.7 × 1.6-2.3 cm; ovaries with ca. 20 ovules per locule; 300-1200 m, Atl. slope and Fila Costeña...P. dodsonii 62 Peduncles ca. 5.5-8 cm long; spathe tube reddish within, mostly green externally; spadix ca. 17-18 × 1.1-1.5 cm; ovaries with (2)3 or 4(5) ovules per locule; 0-20 m, Atl. slope...P. grayumii 56 Epiphytes or loosely scandent vines; largest leaf-blades < 30 cm wide, broadly ovate to lance-ovate or lanceolate. 63 Leaf-blades subreniform to ovate or deltate, < 1.5× as long as wide. 64 Infls. 1-3 per axil; peduncle longer than spadix; ripe frs. bright orange...P. wilburii 64 Infls. solitary in axils; peduncle shorter than spadix; ripe frs. whitish (unknown in P. purpureoviride). 65 Leaf-blades thinly coriaceous, with tertiary veins etched above; midrib yellowish above; spathe with very thick walls (to at least 2.5 cm in fr.); spadix 1.9-2.4 cm thick; 1500-2600 m...P. crassispathum 65 Leaf-blades subcoriaceous, with tertiary veins not etched above; midrib often paler than surface above, but not yellowish; spathe walls < 1 cm thick; spadix ca. 0.8-2.1 cm thick; 0-1000(-1600+) m. 66 Stems drying greenish or dark brown, ± sulcate or striate, the epidermis not notably brittle or exfoliating; spathe tube greenish externally...P. hederaceum 66 Stems drying stramineous to tan, smooth, the epidermis thin and brittle, exfoliating; spathe tube purplish externally...P. purpureoviride 63 Leaf-blades narrowly ovate to lanceolate, > 1.5× as long as wide. 67 Short-stemmed, appressed-climbing canopy epiphytes; petioles 34-71 cm long; peduncles 4-7 cm long, < half as long as spadices; spadix 13.5-19.5 × 1-1.8 cm; 0-350 m, Atl. slope...P. aromaticum 67 Long-stemmed plants, appressed-climbing or loosely scandent; petioles 8-65.5 cm long; peduncles 2-19 cm long, usually > half as long as spadices; spadix (5.1-)6.1-14.5 × (0.5-)0.6-1.8 cm; 0-2000 m, both slopes. 68 Petioles 8-28 cm long; leaf-blades with 2-4(5) primary lateral veins per side; infls. solitary...P. purpureoviride 68 Petioles 12-65.5 cm long; leaf-blades with 3-11 primary lateral veins per side; infls. 1-4 per axil. 69 Petioles firm, with ± thickened, often purplish, distal "geniculum"; peduncles 2.5-11 cm long, shorter than spadices; ripe frs. whitish...P. sagittifolium 69 Petioles ± spongy (easily compressible), lacking a distal "geniculum"; peduncles 2.5-19 cm long, usually longer than spadices; ripe frs. bright orange (unknown in P. straminicaule). 70 Fertile stems ca. 1-3 cm thick; leaf-blades ca. 2+× as long as wide; spadix 10-14.5 cm long; ovaries with 4 or 5 ovules per locule; 1000-1800+ m, Pac. slope Cord. Talamanca...P. cotonense 70 Fertile stems usually < 2 cm thick; leaf-blades usually < 2× as long as wide; spadix (5.1-)6.1-11.6(-12.9) cm long; ovaries with 1 or 2 ovules per locule; 0-2000 m, widespread. 71 Internodes 1-5(-12) cm long; ripe frs. greenish white to lavender; 1100-1400 m, Cord. Guanacaste...P. straminicaule 71 Internodes 3-15 cm long; ripe frs. bright orange; 0-2000 m, widespread...P. wilburii Philodendron alliodorum Croat & Grayum, in Grayum, Phytologia 73: 30. 1992. Shrubby, branching plants clambering to at least 10 m above ground on tree-trunks. Cataphylls lacking. Petioles ca. 5.6-13.6 cm, involute-sheathed to within 0.5 cm of blade. Leaf-blades ca. 13.4-32.2 × 3.2-14 cm, elliptical to lanceolate or oblanceolate, cuneate to truncate or rounded (and often minutely cordulate) at base, with ca. 10-14 primary lateral veins per side. Infls. 1 (rarely 2), terminal on branches. Peduncles (0.6-)1.1-3.5 cm. Spathe tube uniformly whitish within. Spadix 5.9-12.3 × 0.6-1.2 cm. Ripe frs. ochroleucous, with garlicky odor. Wet forests, 0-700 m; entire Atl. slope, Pac. slope S from R.B. Carara. Fl. Jan.-Aug., Nov. NE Nic. to Pac. Ecua. (Croat & Grayum 59720; CR, MO) Plants of Philodendron alliodorum are rather nondescript, best characterized by their branching habit, relatively short petioles (less than half as long as the blades) with involute, scarious-margined sheaths extending to near the leaf-blade base, and narrow, non-cordate, markedly inequilateral blades with numerous (10-14 pairs) primary lateral veins. The foliage dries a characteristic reddish brown color. This sp. is most easily confused with P. inaequilaterum, but differs in having even more strongly inequilateral blades, mostly solitary infls., and whitish (rather than bright orange) frs. Philodendron alticola Croat & Grayum, in Croat, Ann. Missouri Bot. Gard. 84: 394. 1997. Vine on tree-trunks to at least 6 m above ground. Cataphylls deciduous or (usually) persistent as network of fibers. Petioles ca. 35-51+ cm, subterete or somewhat flattened above. Leaf-blades ca. 43-75 × 22-47 cm, ovate to oblong, deeply cordate at base, with ca. 6-9 primary lateral veins per side. Infls. usually 1 or 2 per axil. Peduncles ca. 5-6(-11) cm. Spathe tube reddish or purplish within. Spadix ca. 7-11 × 1.2-2 cm. Ripe frs. white. Oak forests, 2300-2500 m; Atl. slope Cord. Talamanca near Pan. border. Fl. Sep. CR and extreme W Pan. (Prov. Chiriquí). (Davidse et al. 28735; CR, MO) Only one other spp. of Philodendron (cf. P. crassispathum), and few other Araceae, grow at such high elevations as P. alticola. In its ovate-cordate leaf-blades and (especially) stout spadix, P. alticola is most reminiscent of P. schottianum, which ascends nearly as high. It differs from the latter sp. in its more loosely scandent habit, somewhat smaller size, deciduous cataphylls sometimes leaving a few fibers, and generally smaller spadices. Philodendron angustilobum Croat & Grayum, in Croat, Ann. Missouri Bot. Gard. 84: 396. 1997. Appressed-climbing epiphytic vines, fertile to at least 6 m above ground. Cataphylls deciduous intact. Petioles ca. 25-46 cm, spongy, subterete (more shallowly rounded above, the margins obtuse to rounded). Leaf-blades ca. 33-48 × 22-44 cm, deeply hastately trilobate with medial lobe ca. 6-13 cm wide, shallowly to ± deeply cordate at base, with ca. 5-9 primary lateral veins per side. Infls. 1 or 2 per axil. Peduncles ca. 9-15 cm. Spathe tube reddish within at base. Spadix ca. 15-16 × 0.9 cm. Ripe frs. unknown. Wet forests, 30-700 m; Atl. slope Cord. Central (E.B. La Selva, Florencia de Turrialba), very rare Pac. slope (R.B. Carara). Fl. May, Jul., Aug. Hond. to W cent. Pan. (Cerro Campana). (Grayum & Chavarría 8302, MO) This is a rare sp., recognized by its low-elevation habitat, spongy petioles and deeply hastately lobed, blackish-drying leaf-blades. In most respects it resembles P. ligulatum which, however, has unlobed blades. Philodendron angustilobum comprises appressed trunk epiphytes flowering rather high above the ground, hence not easily discerned. Though extremely rare at E.B. La Selva, this sp. is locally abundant at the Turrialba site. The only collection from the Pac. slope (Bello & Rojas 2286, INB) has a smallish, but perhaps immature, infl. Philodendron anisotomum Schott, Oesterr. Bot. Z. 8: 179. 1858. P. trisectum Standl. Mata de culebra, daguilla. Appressed-climbing epiphytic vines (rarely epilithic), fertile ca. 1.5-5 m above the ground. Cataphylls deciduous intact. Petioles 19-60 cm, often ± spongy, terete or subterete. Leaf-blades ca. 12.5-34 × 14.5-41 cm, very deeply trilobate with the lateral lobes weakly to very strongly curved forward and medial lobe 2.2-10.4 cm wide, broadly cuneate to truncate or subcordate or (rarely) cordate at base, with 2-5(-7) primary lateral veins per side. Infls. 1 or 2 per axil. Peduncles 8-22 cm. Spathe tube deep reddish or purplish within. Spadix ca. 7.7-13.3 × 0.6-1 cm. Ripe frs. red-orange. Wet and moist forests, often in disturbed sites, (600-)800-2000+ m; both slopes Cords. Tilarán and Central, Pac. slope Cord. Talamanca, Valle Central, Montes del Aguacate, Cerro Caraigres. Fl. Jan.-May, Jul.-Dec. W Mex. (Nayarit) to CR. (Haber & Zuchowski 9518; CR, MO) This familiar sp. is readily distinguished by its somewhat spongy petioles, glossy, bright green, deeply tripartite leaf-blades with rather short, ± falcate lateral lobes, and bright orange ripe frs. Philodendron anisotomum has the highest average elevational range of any CR Philodendron sp. with trilobate leaf-blades. It might perhaps be confused with P. rothschuhianum or P. tripartitum, the only other common spp. in this group, but those spp. have more numerous primary lateral leaf veins than P. anisotomum as well as whitish, rather than orange, frs. Philodendron anisotomum is commonly cult. as an ornamental in parks and yards, on the Valle Central and elsewhere. Philodendron aromaticum Croat & Grayum, in Croat, Ann. Missouri Bot. Gard. 84: 403. 1997. Rather short-stemmed, appressed-climbing trunk epiphytes, usually high in canopy but descending in well-lit sites to ca. 3 m above ground (or occasionally fallen on ground). Cataphylls deciduous intact. Petioles ca. 34-71 cm, spongy, subterete. Leaf-blades ca. 36-56 × 15-29 cm, narrowly ovate to sagittate, deeply and ± narrowly cordate at base, with ca. 4-9 widely spreading primary lateral veins per side, subcoriaceous. Infls. 1 or 2 per axil. Peduncles ca. 4-7 cm. Spathe tube deep reddish or purplish within. Spadix 13.5-19.5 × 1-1.8 cm. Ripe frs. unknown. Wet forests, 0-350 m; Atl. slope Cord. Central (to R.N.F.S. Barra del Colorado). Fl. Jan.-Mar., Sep., Oct., Dec. ENDEMIC (though certainly will be found in SE Nic.). (Davidse & Herrera 31212; CR, MO) Philodendron aromaticum is distinguished by its lowland Atl. habitat, canopy habit, deciduous cataphylls, ± sagittate leaf-blades, and short peduncles (relative to the spadix). It is perhaps most likely to be confused with the variable P. sagittifolium, but the latter sp. is generally lower growing and has firm, distally geniculate petioles, potentially more numerous infls. and longer peduncles, and consistently shorter spadices. The crushed petioles and foliage of P. aromaticum yield a strong and characteristic terpenoidal odor, as reflected in the epithet. Philodendron aurantiifolium Schott, Oesterr. Bot. Z. 8: 178. 1858. P. guttiferum sensu Standl. (1937, pro parte), Fl. Guatemala (pro parte), Fl. Panama (pro parte), non Kunth. Much-branched vines, clambering atop shrubs or understory trees or densely covering trunks of larger trees to at least 10 m above ground. Cataphylls lacking. Petioles 5-17.1 cm, with horizontally spreading sheath extending to within 1 cm of blade. Leaf-blades (7.9-)11-19.8(-23.5+) × (2.4-)3.7-12.5(-14.8) cm, elliptical, ovate, or deltate to oblong or oblanceolate, cuneate to rounded or subcordate at base, with 5-11 widely spreading primary lateral veins per side. Infls. solitary, terminal on branches. Peduncles (0.2-)0.5-1.7(-2) cm. Spathe tube uniformly cream-colored to pale greenish within. Spadix (6.4-)6.7-13.3 cm. Ripe frs. greenish white to white, translucent (with purplish seeds). Wet forests, 0-1750 m; entire Atl. slope, Pac. slope Cord. Talamanca and in lowlands S from R.B. Carara, Cerro Azahar, Montes del Aguacate. Fl. Jan.-Nov. Extr. S Mex. (Chis.) to W cent. Pan. (Liesner et al. 15238; CR, MO) Philodendron aurantiifolium is a common sp., well characterized by its branching habit, extensive, broadly splayed petiole sheaths, and smallish, non-cordate leaf-blades The only spp. with which it may be easily confused are P. burgeri (in the Pac. lowlands) and the very rare P. rojasianum (see key, couplet 11) and P. tuerckheimii (see under that entry). Philodendron sulcatum is superficially similar, but comprises mostly appressed-climbing, unbranched or sparingly branched plants with frequently paired infls. subtended by cataphylls. Two subspp. of Philodendron aurantiifolium are widespread in CR: the lowland (0-1200 m) subsp. aurantiifolium, and the cloud-forest (700-1750 m) subsp. calderense (K. Krause) Grayum [Syst. Bot. Monogr. 47: 199. 1996; P. calderense K. Krause, in Engl. & K. Krause, Pflanzenr. IV.23Db (Heft 60): 8. 1913]. The latter taxon (Grayum 5362; CR, MO) is characterized by longer petioles with the sheath more prolonged distally, slightly larger, blackish-drying leaf-blades with more numerous primary lateral veins, and slightly longer spadices. They are very rarely found together (Fila Matama, Cord. Talamanca). Both subspp. range widely in the Mesoamerican region, from S Mex. (subsp. calderense) or Guat. to W Pan. Philodendron auriculatum Standl. & L. O. Williams, Ceiba 3: 108. 1952. Tabacón imperial. Short-stemmed, appressed-creeping trunk epiphytes, usually high in canopy, but descending in well-lit sites to ca. 4 m above ground (or occasionally fallen on ground), rarely epilithic. Cataphylls ultimately deciduous intact. Petioles ca. 17-49 cm, spongy, terete. Leaf-blades 37-75 × 8-24.5 cm, ± narrowly elliptical to lance-oblong, truncate to rounded or auriculate at base, with ca. 11-27 primary lateral veins per side. Infls. solitary in axils. Peduncles ca. 5-13.5 cm. Spathe tube deep reddish within. Spadix ca. 11-20 × 0.9-1.6 cm. Ripe frs. orange. Wet forests, 0-1000 m; Pac. slope S from R.B. Carara. Fl. Jan.-Mar., Sep.-Nov. ENDEMIC. (Burger & Liesner 7298; CR, MO) Its short-stemmed, epiphytic habit, markedly spongy, terete petioles, and narrow, non-cordate leaf-blades immediately distinguish Philodendron auriculatum from all other CR spp. except the very similar P. wendlandii. The latter sp. is restricted to the Atl. lowlands, and differs further in its rosulate habit and shorter, D-shaped petioles. Like P. wendlandii, Philodendron auriculatum is often grown as a patio ornamental in CR, especially in areas where it is native. Philodendron bakeri Croat & Grayum, in Croat, Ann. Missouri Bot. Gard. 84: 406. 1997. High-climbing, epiphytic vines, the fertile stems pendent and often hanging to within ca. 2-5 m above the ground. Cataphylls deciduous intact. Petioles 4-12 cm, subterete to slightly flattened or canaliculate above with the margins obtuse to rounded, purplish distally (on "geniculum"). Leaf-blades 13.7-26 × 4.5-10.4 cm, narrowly to broadly oblong or elliptical, lanceolate, or oblanceolate (rarely lance-ovate), cuneate to rounded, truncate or subcordate at base, with ca. 4-7 ± obscure primary lateral veins per side. Infls. solitary in axils. Peduncles ca. 1.6-6.7 cm. Spathe tube deep reddish within (and sometimes externally as well). Spadix ca. 6.5-8.7 × 0.7-1.1 cm. Ripe frs. unknown. Wet forests, 0-1000 m; Atl. slope Cords. Guanacaste, Tilarán, and Central (to vic. Tortuguero). Fl. Jan.-Apr., Dec.. NE Nic. to E Pan. (Grayum et al. 4992; CR, MO) Philodendron bakeri is distinguished by its high-climbing habit, smallish, non-cordate leaf-blades, and solitary, short-pedunculate infls. It might be confused with the sympatric P. ligulatum, but the latter sp. has spongy petioles, larger leaf-blades with more numerous primary lateral veins, and longer peduncles and spadices. Certain leaf types of P. sagittifolium (e.g., on juvenile or flagelliform shoots) may be virtually indistinguishable form normal foliage leaves of P. bakeri, especially in terms of petiole structure and coloration. However, even precociously flowering specimens of the former sp. have 1-4 infls. per axil and uniformly longer spadices. Philodendron brenesii Standl., Fl. of Costa Rica 140. 1937. Thick-stemmed vines climbing to at least 3.5 m above the ground on trunks or branches, or often terrestrial or growing over rocks or stumps. Cataphylls ultimately deciduous intact. Petioles 14.3-58+(-100?) cm, somewhat spongy, subterete (low-convex to virtually flattened above with the margins rounded, convex below). Leaf-blades ca. 31-80+ × 15-42 cm, lance-ovate or ± narrowly oblong-lanceolate, deeply cordate to sagittate at base, subcoriaceous to coriaceous, matte and glaucous below, with ca. 10-22 primary lateral veins per side (these spreading at ca. a 90ƒ angle, at least in proximal half of blade), the midrib paler than surface on both sides (sometimes reddish above). Infls. 1-3 per axil. Peduncles 3-9.5 cm. Spathe tube deep reddish or purplish within. Spadix 8-17 × 0.9-2.1 cm (proportionately stouter in material from higher elevations). Ripe frs. orange. Wet forests, 800-2200 m; Atl. slope and near Continental Divide, all main cords. Fl. Apr., May, Jul.-Sep., Nov. CR and W Pan. (Herrera 5384; INB, MO) This striking sp. is easily recognized by its stout stems and ± sagittate, thickish leaf-blades, glossy above and matte and glaucous below, with numerous, prominently spreading primary lateral veins. It might perhaps be confused with narrower leaved, epiphytic forms of P. thalassicum, but plants of the latter sp. have persistent cataphyll fibers, fewer primary lateral leaf veins, and spathe tubes uniformly greenish within. Philodendron brenesii is frequently cult. as an ornamental on the Valle Central, and elsewhere in upland CR. Philodendron brevispathum Schott, Bonplandia 7: 29. 1859. Vines on trees, or occasionally on ground, usually fertile ca. 1-2.5 m above the ground, the stems with light brown, uniformly scabrous, often exfoliating epidermis. Cataphylls subpersistent, ultimately deciduous or deliquescent (but not weathering to fibers). Petioles ca. 12.5-41.5 cm, ± spongy, terete or subterete (obscurely flattened above). Leaf-blades 18.5-41 × 11.4-24 cm, narrowly to broadly ovate to deltate, deeply cordate to sagittate or subhastate at base, with 5-8 primary lateral veins per side. Infls. 1(-3) per axil. Peduncles ca. 2.1-7.5 cm. Spathe tube green within. Spadix ca. 6.4-9.5 × 0.5-1.1 cm. Color of ripe frs. unknown. Wet (swampy) forests, 0-110 m; entire Atl. slope. Fl. Feb.-Apr., Jun., Aug., Sep. NE Nic. to Bol., Ven., Braz. (Robles 1877; CR, MO) Philodendron brevispathum is an uncommon sp. of swampy habitats on the Atl. coastal plain. Its finely and uniformly scabrous stem epidermis immediately sets P. brevispathum apart from all other CR Philodendron spp. except P. jacquinii, which occurs in drier (usually Pac.) habitats and has spathe tubes reddish within. Philodendron brunneicaule Croat & Grayum, in Croat, Ann. Missouri Bot. Gard. 84: 414. 1997. Thick-stemmed, appressed-climbing vines on trunks, often rooted in ground, usually fertile ca. 3.5-12 m above the ground, the stems with reddish brown, smooth to patchily pustular, exfoliating epidermis. Cataphylls subpersistent, ultimately deciduous or deliquescent (but not weathering to fibers). Petioles ca. 29-65 cm, flattened to shallowly concave above, rounded below, the margins obtuse. Leaf-blades 33-70 × 22-53 cm, ± broadly ovate, deeply cordate at base, with ca. 7-12 primary lateral veins per side. Infls. solitary in axils, often borne well below the stem apex. Peduncles 6.5-21.5 cm. Spathe tube deep red within. Spadix ca. 11-18.7 × 1-2 cm. Color of ripe frs. unknown. Wet forests, 50-950 m; Atl. slope Cords. Tilarán and Central. Fl. Apr., May, Jul., Aug., Oct. CR to E Pan. (Stevens 13859; CR, MO) This uncommon sp. is well characterized by its appressed-climbing habit, long internodes with reddish brown, exfoliating epidermis, large, thin, cordate, brownish-drying leaf-blades, and solitary, relatively long-pedunculate infls. usually borne well below the stem apex. Philodendron brunneicaule is not confused with any other CR spp. Philodendron burgeri Grayum, Syst. Bot. Monogr. 47: 188. 1996. P. guttiferum sensu Standl. (1937, pro parte), non Kunth. Slender-stemmed vines climbing to at least 10 m above the ground on trunks, the branches mostly pendent. Cataphylls lacking. Petioles (4.9-)5.2-10.4 cm, with horizontally spreading sheath extending to within 1 cm of blade. Leaf-blades (9.7-)13-21.6 × (2.9-)3.7-9.6 cm, narrowly lanceolate to narrowly ovate, narrowly or broadly elliptical, or oblanceolate, cuneate to rounded or subtruncate at base, with ca. 5-7(-10) primary lateral veins per side. Infls. solitary, terminal on the branches. Peduncles (1-)1.6-2.4 cm. Spathe tube uniformly yellow-green within. Spadix 8.6-13.6 × 0.7-0.9 cm. Ripe frs. cream-colored. Wet forests, 0-250(-850) m; Pac. slope S from Z.P. El Rodeo and vic. Orotina. Fl. Jan.-Apr. CR and W Pan. (Pen. Azuero). (Grayum et al. 4760; CR, MO) Philodendron burgeri is characterized by its Pac. lowland habitat, branching, high-climbing habit with slender, pendent stems, horizontally splayed petiole sheaths, and smallish, non-cordate leaf-blades. The only spp. in its range with which it might be confused are the very similar P. aurantiifolium and the likewise similar, though much rarer, P. tuerckheimii. It differs from the former in its relatively shorter petioles and longer peduncles, from the latter in its more narrowly alate petiole sheaths and greenish- (rather than brownish-) drying leaf-blades with less prominent resin ducts, and from both in its minutely alveolate leaf-blade surfaces and proportionately shorter female spadix portion (less than 1/4 the total spadix length). Philodendron chirripoense Croat & Grayum, in Croat, Ann. Missouri Bot. Gard. 84: 417. 1997. Hanging from a tree limb in forest. Cataphylls deciduous intact. Petioles ca. 7-7.3 cm, the cross-sectional shape undescribed. Leaf-blades ca. 11.5-11.9 × 5.3-5.8 cm, ovate, subcordate at base, long-acuminate at apex, with ca. 4 or 5 primary lateral veins per side. Infl. solitary in axil. Spathe tube reddish within. Peduncle 6 cm long. Spathe tube reddish within. Spadix length and maximum width unknown. Ripe frs. unknown. Wet forests, 1000 m; Pac. slope Cord. Talamanca (upper Río General Valley). Fl. Dec. ENDEMIC. (Burger & Liesner 7139, F) Philodendron chirripoense is known only from the type collection. This may prove to represent nothing more than a depauperate specimen of some other sp., e.g., P. wilburii. Philodendron cotobrusense Croat & Grayum, in Croat, Ann. Missouri Bot. Gard. 84: 422. 1997. Appressed-climbing epiphytes. Cataphylls unknown. Petioles ca. 34.5 cm, subterete (obscurely flattened or concave above). Leaf-blades ca. 35 × 32 cm, very deeply trilobate with the lateral lobes curved forward and medial lobe ca. 17 cm wide, ± cordate at base, with ca. 20-22 primary lateral veins per side. Infls. to at least 5 per axil. Peduncles ca. 4.5-6.3 cm. Spathe tube solid red-violet within. Spadix ca. 10-11.5 × 0.8-1 cm. Ripe frs. unknown. Wet forest, 1250 m; Pac. slope S Cord. Talamanca (vic. Las Alturas de Coto Brus). Fl. Jul. ENDEMIC. (Grayum & Hammel 5689; CR, MO) Philodendron cotobrusense, known only from the type collection, is very similar to P. tripartitum, from which it differs principally in having wider medial leaf-blade lobes with more numerous primary lateral veins, and potentially more numerous infls. in the axils. The last-mentioned character is the most diagnostic, as Pac. slope populations of P. tripartitum tend to have unusually wide medial lobes with numerous primary lateral veins. Indeed, the possibility that P. cotobrusense is merely an extreme variant of P. tripartitum cannot be disregarded. Philodendron cotonense Croat & Grayum, in Croat, Ann. Missouri Bot. Gard. 84: 423. 1997. Thick-stemmed, appressed-climbing vines, fertile to at least 4-5 m above the ground. Cataphylls deciduous intact. Petioles 18-55 cm, rounded below, low-convex to flattish above, the margins rounded. Leaf-blades 21-45 × 10-22 cm, lance-ovate or lance-deltate to oblong-lanceolate, ± deeply cordate to sagittate or subhastate at base with 5-9(-11) primary lateral veins per side. Infls. 1 or 2 per axil. Peduncles 6.5-19 cm. Spathe tube deep reddish or purplish within. Spadix ca. 10-14.5 × 0.7-1 cm. Ripe frs. bright orange. Wet forests, 1000-1800+ m; Pac. slope S Cord. Talamanca (Coto Brus region), Fila Costeña. Fl. Mar., Jun., Aug., Sep., Nov., Dec. CR and extreme W Pan. (Prov. Chiriquí). (Grayum et al. 8113; CR, MO) Philodendron cotonense is distinguished by its thickish stems with silvery-gray epidermis, proportionately narrow, ± sagittate leaf-blades, relatively long-pedunculate infls., and bright orange frs. It is very similar and only weakly separated from the likewise orange-fruited, more widespread P. wilburii, which differs in having more slender stems, generally smaller, proportionately wider leaf-blades, smaller infls., and ovaries with fewer ovules per locule (see key, couplet 70). The two entities appear to behave as separate spp. at sites where they co-occur (e.g., Cerro Anguciana, S Fila Costeña). Philodendron crassispathum Croat & Grayum, in Croat, Ann. Missouri Bot. Gard. 84: 425. 1997. Thick-stemmed, loosely scandent, epiphytic vines, fertile ca. 2.5-4 m above the ground, or occasionally terrestrial. Cataphylls subpersistent, ultimately deciduous. Petioles 12-40 cm, somewhat spongy, ± rounded below, low-convex to flattened above, the margins obtuse to rounded. Leaf-blades 12.5-30.5 × 9.5-23.2 cm, subreniform to broadly ovate, elliptical, or oblong-ovate, deeply cordate to subsagittate at base, coriaceous, with ca. 4-6 primary lateral veins per side, the midrib yellowish above. Infls. apparently solitary in the axils. Peduncles ca. 1.5-6 cm, very stout. Spathe tube deep reddish within, very thick-walled (to at least 2.5 cm in fr.). Spadix ca. 7.7-11.5 × 1.9-2.4 cm. Ripe frs. white (with yellow-orange seeds). Wet forests, ca. 1500-2600 m; Atl. slope and near Continental Divide, Cords. Tilarán, Central, and Talamanca, Cerro Azahar. Fl. Feb.-Jul., Sep. CR and W Pan. (Herrera & Gamboa 6219; INB, MO) This sp. is unmistakable by virtue of its montane habitat, stout stems, smallish, cordate, coriaceous leaf-blades with the midrib yellowish above, and short-pedunculate, very thick-walled spathes. Though resembling P. brenesii in terms of leaf-blade texture and coloration, it is not confused with any other CR Philodendron. Philodendron cretosum Croat & Grayum, in Croat, Ann. Missouri Bot. Gard. 84: 427. 1997. Appressed-climbing trunk epiphytes, fertile ca. 2.5-6 m above the ground, cut parts yielding a clear sap which becomes chalky-white upon oxidation. Cataphylls persistent, weathering to whitish fibers. Petioles 9.5-21 cm, sulcate above, rounded below, the margins obtuse. Leaf-blades 42-72 × (4.6-)6.4-13.1 cm, narrowly oblong or elliptical to oblanceolate, attenuate to cuneate at base, with ca. 7-12 primary lateral veins per side. Infls. 1-3 per axil. Peduncles ca. 3.3-6 cm. Spathe tube uniformly greenish within and without. Spadix ca. 7.5-11 × 0.9-1.6 cm. Ripe frs. unknown. Wet forests, 0-600(-950) m; entire Atl. slope. Fl. Jan., Apr., Jun., Aug., Nov. CR (and probably SE Nic.) to E Pan. (Grayum 9022; INB, MO) This uncommon sp. is unique among CR Philodendron in having chalky-white sap (the sap is clear at first, but turns white on oxidation). It is additionally distinctive in its appressed-climbing habit, persistent cataphyll fibers, narrow, cuneate-based leaf-blades, and relatively short-pedunculate, uniformly greenish spathes. The only other CR sp. with anything close to this combination of characters is the very rare (though sympatric) P. scalarinerve (see key, couplet 28). Philodendron davidsonii Croat, Aroideana 6: 39. 1983. Tabacón holandés. Short-stemmed epiphytes, typically in canopy (fertile to at least 30 m above the ground), but sometimes fallen on ground. Cataphylls deciduous intact, often reddish. Petioles ca. 48.5-86.5 cm, broadly sulcate above, rounded below, the margins obtuse to subacute. Leaf-blades ca. 41.5-77 × 18-43 cm, lance-ovate to broadly lanceolate or oblong-lanceolate, subcordate to cordate or sagittate at base, coriaceous, with ca. 15-25 primary lateral veins per side, the midrib yellow-green to cream-colored above. Infls. 1 or 2 per axil. Peduncles ca. 3.5-7 cm. Spathe tube reddish or purplish within. Spadix ca. 12.5-19.5 × 1-1.8 cm. Color of ripe frs. unknown. Wet forests, 0-100 m; entire Atl. slope. Fl. Mar., May-Aug., Oct. CR and extr. W Pan. (Prov. Bocas del Toro). (Grayum 2931, MO) This seldom-collected sp. of the Atl. coastal plain is distinguished by its canopy habit, short, stout stems, proportionately narrow, subsagittate, many-nerved, thickish leaf-blades with the midrib pale above, and short-pedunculate, large infls. The leaf-blades of juvenile plants are colored solid maroon below. The only other CR sp. with which Philodendron davidsonii might be compared is the very rare P. lentii (see key, couplet 55). Philodendron davidsonii is of significant horticultural value, and has been cult. for ornament both locally and abroad. CR material of this sp. belongs to subsp. davidsonii, with the same geographic range as the sp. Philodendron dodsonii Croat & Grayum, in Croat, Ann. Missouri Bot. Gard. 84: 430. 1997. Robust, appressed-climbing trunk epiphytes, fertile ca. 2.5-5 m above the ground, the stems to ca. 8 cm wide. Cataphylls deciduous intact, or subpersistent and weathering to fine fibers. Petioles ca. 55-108 cm, subterete to low-convex or ± flattened above (especially distally), the margins ± rounded to obtuse. Leaf-blades ca. 46-106 × 30-70 cm, ovate, deeply cordate at base, with ca. 7-11 primary lateral veins per side. Infls. ca. 1-5 per axil. Peduncles ca. 9-14.5(-17.5) cm. Spathe tube deep reddish within and without, the lamina whitish. Spadix ca. 11.5-16.7 × 1.6-2.3 cm. Ripe frs. white. Wet forests, ca. 300-1200 m; Atl. slope Cords. Tilarán, Central, and Talamanca, Pac. slope Fila Costeña (S from vic. Dominical). Fl. Jun.-Sep. CR and Pac. Ecua. (Grayum et al. 8112, MO) Philodendron dodsonii is an uncommon sp., best recognized by its coarse, appressed-climbing habit, subterete petioles, very large, cordate leaf-blades, and large infls. with the spathe tube reddish on both surfaces and the blade contrastingly whitish. It is perhaps most similar to the poorly known P. dominicalense (which see) and also to P. pterotum, which differs in having undulate-winged petioles. It might also be confused with the lower elevation P. grayumii and the mainly higher elevation P. schottianum, but those spp. have shorter peduncles and spathe tubes mostly greenish externally. Philodendron dominicalense Croat & Grayum, in Croat, Ann. Missouri Bot. Gard. 84: 434. 1997. Robust, appressed-climbing trunk epiphytes, [fertile ca. ? m above the ground], the stems to ca. 2-5 cm diam. Cataphylls persisting semi-intact. Petioles 37-74 cm, subterete, weakly flattened above distally. Leaf-blades ca. 41-46 × 19-37.5 cm, ovate, deeply cordate at base, with ca. 4-6 primary lateral veins per side. Infls. 2 per axil. Peduncles 8-9 cm. Spathe green throughout. Spadix ca. 9.7-10.3 × 0.7-1.3 cm. Ripe frs. unknown. Wet forests, ca. 1000 m; Pac. slope Fila Costeña (San Isidro de El General/Dominical). Fl. May. ENDEMIC. (Croat 35268, MO) Philodendron dominicalense is a very poorly understood entity, known by just two collections from the same small area. Vegetatively, it is virtually indistinguishable from the widespread P. dodsonii. The difference in ovule number emphasized in the original description of P. dominicalense (see key couplet 57) is extremely significant, but needs to be substantiated; it would segregate these two spp. into different sections of P. subg. Philodendron. Philodendron ensifolium Croat & Grayum, in Grayum, Phytologia 73: 32. 1992. Appressed-climbing, understory trunk epiphytes, fertile ca. 2-7 m above the ground. Cataphylls borne only among infls. (deciduous intact). Petioles (12.8-)13.1-29.9 cm, with erect to spreading sheath extending to within 1 cm of (and usually prolonged beyond) base of blade. Leaf-blades (26.7-)34.1-54.4 × (2.0-)4.5-10.9 cm, linear-lanceolate to narrowly lanceolate or (rarely) oblanceolate, broadly cuneate to truncate or rounded (rarely subcordulate) at base, with ca. 3-6 obscure primary lateral veins per side. Infls. 1 or 2(3) per axil. Peduncles (0.8-)1.7-4.2(-8.5) cm. Spathe tube greenish white within, becoming uniformly yellow-orange to orange-yellow externally in fr. Spadix 8.2-11.9 × 0.5-1.2 cm. Ripe frs. apparently translucent-whitish, with pinkish seeds. Wet forests, 0-600 m; Atl. slope Cords. Guanacaste, Tilarán, Central (to R.N.F.S. Barra del Colorado), and N Cord. Talamanca (vic. Siquirres). Fl. May-Aug. CR (and probably extreme SE Nic.) to Pac. Col. (Rivera 1476, INB) Philodendron ensifolium is recognized by its appressed-climbing habit, fully sheathed petioles, and very narrow (> 4× as long as wide), non-cordate, highly glossy leaf-blades with obscure primary lateral veins. It is most likely to be confused with P. rhodoaxis, which has less extensive petiolar sheathing and ± matte, proportionately wider leaf-blades with more prominent and much more numerous primary lateral veins. Philodendron ensifolium also approaches P. herbaceum (see key, couplet 5). CR material of this sp. belongs to subsp. ensifolium, with the same geographic range as the sp. Philodendron findens Croat & Grayum, in Croat, Ann. Missouri Bot. Gard. 84: 440. 1997. Coarse, appressed-climbing trunk epiphytes, fertile ca. 3-6 m above the ground. Cataphylls persistent, weathering to brownish fibers. Petioles ca. 42-124 cm, finely striate, virtually flat above, rounded below, the margins sharply and narrowly winged, the wings erect to spreading, becoming crispate-undulate distally. Leaf-blades ca. (25-)34-70 × (18-)28-65 cm, ovate or ± deltate, entire when flushed but soon tearing between all primary lateral veins, cordate to subsagittate at base, with ca. 7-11 primary lateral veins per side. Infls. 1-3 per axil. Peduncles ca. 5.5-13 cm. Spathe tube deep red to purplish within, green externally. Spadix ca. 10.5-17.5 × 1.1-1.8 cm. Ripe frs. unknown. Wet forests, 100-1400 m; Atl. slope Cords. Tilarán, Central, and Talamanca. Fl. May-Sep., Nov. CR to E cent. Pan. (and possibly W Col.). (Grayum 10924; INB, MO) Philodendron findens is unique among CR congeners in its leaf-blades, which become pinnatifid by tearing. It is otherwise very similar to P. pterotum (see key, couplet 30). Compare also with P. radiatum, the leaf-blades of which are deeply pinnately to bipinnately lobed from the start. Philodendron fragrantissimum (Hook.) G. Don, in Sweet, Hort. brit. ed. 3 632. 1839. Caladium fragrantissimum Hook., Bot. Mag. 61: t. 3314. 1834. Appressed-climbing trunk epiphytes, fertile ca. 3.5-5 m above the ground. Cataphylls persistent, weathering to reddish brown fibers. Petioles ca. 20-56 cm, flat or broadly concave above, rounded below, the margins obtuse to acute. Leaf-blades ca. 21-52 × 15-38 cm, ovate to deltate, cordate to subsagittate at base, with ca. 5-7 primary lateral veins per side. Infls. 1-3 per axil. Peduncles ca. 3.5-10(-17) cm. Spathe tube deep red to purplish within and without, the lamina whitish. Spadix ca. 8.7-12.2 × 0.7-1.1 cm. Ripe frs. red. Wet forests, 0-300+ m; entire Atl. slope, S Pac. slope (head of Golfo Dulce). Fl. Jan., Jul.-Sep. Bel. and E Guat. to Perú, Guianas, Braz., Cuba. (Stevens 24119; CR, MO) Philodendron fragrantissimum is distinguished by its appressed-climbing habit, persistent, reddish cataphyll fibers, D-shaped petioles, glossy, cordate leaf-blades, externally red spathe tube, and red frs. It is perhaps most similar to P. tenue, but the latter sp. has terete petioles, more numerous primary lateral leaf veins, and whitish frs. The application of this name to Cent. Amer. material is questionable. Philodendron grandipes K. Krause, in Engl. & K. Krause, Pflanzenr. IV.23Db (Heft 60): 48. 1913. P. pleistoneurum Standl. & L. O. Williams. Terrestrial herbs, the stems decumbent and subrhizomatous, rarely appressed-climbing on trunk bases. Cataphylls persistent, eventually weathering to brownish fibers. Petioles ca. 35-69 cm, broadly to weakly convex above, rounded below, the margins acute. Leaf-blades ca. 22-46 × 19-38 cm, rotund to broadly ovate, deltate or oblong-ovate, deeply cordate to subsagittate at base, with ca. 9-15 primary lateral veins per side. Infls. 1-4 per axil. Peduncles ca. 4-14.2 cm. Spathe tube uniformly pale green within and green without, to deep pinkish, reddish or purplish within and without. Spadix ca. 5.6-9.9 × 0.7-1.1 cm. Ripe frs. white. Wet forests, 0-700(-1200) m; entire Atl. slope, Pac. slope S from Puriscal region. Fl. Mar.-Sep., Dec. SE Nic. to E Pan., S Pac. Col. and Pac. Ecua. (Stevens 24119; CR, MO) Philodendron grandipes is one of the very few characteristically terrestrial Philodendron spp. in CR (see also P. strictum, P. thalassicum), and the only one in the lowlands. It is additionally distinctive in its cordate leaf-blades with numerous primary lateral veins and long-pedunculate but small infls. Perhaps the most similar sp. is the epiphytic P. jodavisianum, which has proportionately narrower leaf-blades and relatively shorter peduncles. Because of its terrestrial habit, P. grandipes has sometimes been confused with Homalomena wendlandii (which see). This is the only CR Philodendron that is dimorphic with regard to the coloration of the inner surface of the spathe tube (greenish vs. reddish). Populations on the Atl. slope tend to have uniformly green spathes and those on the Pac. slope reddish spathes, but there are exceptions on both counts. This sp. is known from above 700 m elevation only in the Pac. Fila Costeña. Philodendron grayumii Croat, Ann. Missouri Bot. Gard. 84: 452. 1997. Appressed-climbing trunk epiphytes, fertile ca. 3.5-5 m above the ground (occasionally on the ground). Cataphylls deciduous intact. Petioles ca. 37-97 cm, subterete (low-convex to obscurely flattened above, rounded below, the margins rounded to subobtuse). Leaf-blades ca. 34-84 × 24.5-57 cm, ovate, deeply cordate at base, coriaceous, with ca. 6-9 primary lateral veins per side. Infls. 1-5 per axil. Peduncles ca. 5.5-8 cm. Spathe tube (and often lamina) deep reddish within, green (or largely so) externally. Spadix ca. 17-18 × 1.1-1.5 cm. Ripe frs. whitish. Wet forests near coast, 0-20 m; Atl. slope S from Puerto Limón. Fl. Aug., Nov. CR and W Pan. (Grayum & Sleeper 4302; CR, MO) This rather nondescript, cordate-leaved sp. is characterized by its appressed-climbing habit, deciduous cataphylls, subterete petioles, and large blades and infls. It most closely resembles the more upland Philodendron dodsonii (see key, couplet 62). Philodendron hederaceum (Jacq.) Schott, Wiener Z. Kunst 1829: 780. 1829. Arum hederaceum Jacq., Enum. syst. pl. 31. 1760; P. micans K. Koch; P. oxycardium Schott; P. pittieri Engl.; P. scandens K. Koch & Sello. Hoja del hombre. Loosely scandent vines, climbing high into trees, the stems hanging down and fertile ca. 2-7+ m above the ground (with the infls. erect); juvenile leaves often shingle-forming and appressed to trunks, or on rocks. Cataphylls deciduous intact. Petioles ca. 12-27 cm, terete or subterete. Leaf-blades 13-37 × 10-25 cm, ovate, ± deeply cordate at base, with ca. 3-6(7) primary lateral veins per side. Infls. solitary in axils. Peduncles ca. 5-9 cm. Spathe tube deep reddish within. Spadix ca. 11-18.5 × 0.8-2.1 cm. Ripe frs. whitish. Wet and moist forests, 0-900 m; throughout the country, Isla del Coco. Fl. Jan.-Mar., Jun., Aug. Mex. (Nay., Jal., SLP) to Bol., Guianas, E Braz., Gr. and Less. Ant. (Grayum et al. 4912; CR, MO) This well known sp. is most commonly seen on trees along rivers or in pastures, but also occurs in primary forest. The loosely scandent, high-climbing and pendent habit, long, smooth internodes, and thickish, cordate, ± ivy-like leaf-blades are characteristic. The sp. with which P. hederaceum is most likely to be confused is the extremely similar P. purpureoviride (see key, couplet 66). Except for its strongly flattened petioles, P. platypetiolatum also bears a resemblance. CR material of P. hederaceum comprises both var. hederaceum and var. kirkbridei Croat (Ann. Missouri Bot. Gard. 84: 463. 1997). The latter (Lent 3591, F), known from 300-900 m elevation on the Atl. slope of Cords. Guanacaste and Central (and S to Pac. Ecua.), differs from the more widespread var. hederaceum in its sulcate, ± warty, reddish-drying stems. Philodendron herbaceum Croat & Grayum, in Grayum, Phytologia 73: 34. 1992. Slender-stemmed vines, clambering among understory shrubs and treelets or climbing on small trunks to no more than ca. 3 m above the ground. Cataphylls occasional, borne only among infls. (deciduous intact). Petioles ca. 7.4-10.5 cm, with involute, scarious-margined sheath extending to within 0.5 cm of (and often prolonged beyond) base of blade. Leaf-blades ca. 10.7-19.9 × 4-8.8 cm, lanceolate to narrowly or ± broadly ovate, oblanceolate, or elliptical, cuneate to rounded or subtruncate at base, with ca. 9-12(-14) primary lateral veins per side. Infls. 1(2) in axils, often terminal on stems. Peduncles ca. 1.6-4(-4.5) cm. Spathe tube ± uniformly light green to white within. Spadix ca. (7.3-)8.4-12.2 × (0.3-)0.45-0.6 cm. Nearly ripe frs. whitish. Wet forests, 0-700 m; Atl. slope Cords. Central (to R.N.F.S. Barra del Colorado) and Talamanca. Fl. Apr.-Oct., Dec. Extr. SE Nic. to E cent. Pan., thence (sporadically) to Pac. Ecua. (Hammel et al. 17529; CR, MO) Philodendron herbaceum is characterized by its low-growing habit, generally small size, persistently green stems, fully sheathed petioles with the sheath involute, ± narrow, non-cordate leaf-blades, and usually solitary infls. with uniformly greenish spathes and slender spadices. It is most likely to be confused with P. rhodoaxis, comprising mostly larger plants with less extensive petiolar sheathing, more strongly inequilateral leaf-blades with more numerous primary lateral veins, and usually paired infls. with longer peduncles. Philodendron herbaceum also approaches P. ensifolium (see key, couplet 5). Philodendron inaequilaterum Liebm., Vidensk. Meddel. Dansk Naturhist. Foren. Kjøbenhavn 1849: 16. 1849. P. coerulescens Engl.; P. guatemalense Engl. Widely branching, rigidly scandent vines loosely draping tree-trunks, climbing to 2-9 m above the ground (or rarely terrestrial or epilithic). Cataphylls borne only among infls., red or reddish, quickly deciduous intact. Petioles (4.3-)8.2-28.4 cm, with erect-spreading to involute sheath extending to within 2.5 cm of leaf-blade base. Leaf-blades (15.6-)18.7-47.2(-54.7) × 5.0-29.6 cm, narrowly or broadly ovate or deltate to elliptical, rarely narrowly lanceolate or oblanceolate, broadly cuneate to rounded or (rarely) truncate or subcordate at base, ± chartaceous, with 11-22 primary lateral veins per side. Infls. (1)2(3) in axils, terminal. Peduncles (0.4-)0.9-4.3 cm. Spathe tube greenish white or cream-colored to (rarely) pinkish within. Spadix (8.5-)10.3-18.1 × 0.45-0.9(-1.05) cm. Ripe frs. deep orange. Moist and wet forests, 0-1000 m; entire Atl. slope, Pac. slope S from Río Grande de Tárcoles. Fl. Feb.-Jun. Mex. (Oax., SLP) to S Pac. Ecua. and W Ven., Amaz. Col. (Dpto. Putumayo). (Grayum & Schatz 5269; CR, MO) Philodendron inaequilaterum is a common, if nondescript sp., recognized by its rangy, scandent habit, non-cordate, chartaceous, many-nerved leaf-blades, usually paired infls. with slender spadices, and deep orange frs. The very rare P. rayanum is extremely similar, but differs in having narrower juvenile leaf-blades and stouter spadices with the female portion proportionately longer. Other spp. easily confused with P. inaequilaterum, especially in vegetative condition, are P. alliodorum and P. schottii (which see for distinguishing features). This is a sp. of ± well-lit, often disturbed habitats, such as riparian forest, secondary forest, abandoned groves, and light-gap edges. Philodendron jacquinii Schott, Syn. Aroid. 90. 1856. P. hederaceum sensu Fl. BCI, non (Jacq.) Schott; P. hoffmannii Schott. Loosely scandent epiphytes on trunks or low shrubs, the stems ± densely asperous, sometimes hanging, fertile to at least 3-10 m above the ground, rarely epilithic. Cataphylls deciduous intact. Petioles ca. 12-46 cm, spongy, terete or obscurely flattened above. Leaf-blades ca. 13-40 × 10.5-28 cm, deltate or ovate, cordate to subhastate at base, with 3-6 primary lateral veins per side, deciduous in dry season. Infls. solitary in axils. Peduncles ca. 5-12 cm. Spathe tube red or purplish within, ± inflated, dehiscent in fr. Spadix ca. 9-12.5 × 0.8-1.6 cm, the pistils distally prolonged. Ripe frs. red-orange. Moist and dry (rarely wet) forests, 0-800(-1300) m; N Atl. slope (very rare; E.B. La Selva), entire Pac. slope. Fl. Nov. Mex. (Oax., Ver.) to N Col., Ven., Cuba. (Bello et al. 20; CR, MO) This relatively uncommon sp. is easily recognized by its (usually) Pac. slope habitat and finely and uniformly asperous stems. The only other CR sp. with such asperous stems is P. brevispathum, which is restricted to wet habitats on the Atl. coastal plain and has uniformly greenish spathes and truncate pistils. Philodendron jodavisianum G. S. Bunting, Gentes Herb. 9: 337. 1965. Appressed-climbing trunk epiphytes, fertile ca. 2-3 m above the ground. Cataphylls persistent, withering to whitish or brownish fibers. Petioles ca. 22-69 cm, flattened above with a medial costa distally, rounded below, the margins acute. Leaf-blades ca. 26-68 × 11.5-34 cm, deltate or narrowly ovate to lance-ovate or oblong-ovate, shallowly to deeply cordate, sagittate, or subhastate at base, with ca. 9-17 primary lateral veins per side. Infls. 1-5 per axil. Peduncles 3-10.5 cm. Spathe tube uniformly greenish within. Spadix 7.5-10 × 0.7-1.3 cm. Ripe frs. whitish. Wet forests, 0-1200+ m; entire Atl. slope, Pac. slope S from R.B. Carara. Fl. Mar., May-Oct. S Mex. (Tab.) to E Pan. (Bello & Haber 2881; INB, MO) Philodendron jodavisianum is a fairly nondescript sp., characterized by its appressed-climbing habit, persistent cataphyll fibers, D-shaped petioles, ± narrow, cordate-based, many-veined leaf-blades, and uniformly green spathes. It is perhaps most similar to the terrestrial P. grandipes, which has proportionately broader leaf-blades and relatively longer peduncles. At higher elevations, it might also be confused with P. thalassicum (see key, couplet 34). Philodendron knappiae Croat, Ann. Missouri Bot. Gard. 84: 475. 1997. Epiphytic or terrestrial. Cataphylls deciduous intact. Petioles ca. 11-22.5 cm, ± flattened above, rounded below, the margins obtuse. Leaf-blades ca. 16.5-26 × 5-14 cm, lance-deltate or -oblong to lanceolate, sagittate at base, subcoriaceous to coriaceous, with 4-8 ± indistinct primary lateral veins per side. Infls. solitary in axils. Peduncles ca. 2-4.5 cm. Spathe tube pinkish within. Spadix ca. 4.5-6(-12) × 0.7-1.4 cm. Ripe frs. unknown. Wet forests, 1200 m; Pac. slope Cord. Talamanca (Tarrazú region). Fl. Nov. CR and W Pan. (Herrera et al. 8789; CR, MO) The single CR collection here referred to Philodendron knappiae most resembles the familiar P. brenesii in general aspect, but differs from that sp. in its smaller leaf-blades with fewer and much more obscure primary lateral veins, and smaller infls. Our collection was provisionally included in P. brenesii by Croat (1997: 411), who suggested that it might represent an undescribed sp. Further investigation is clearly needed. Philodendron lentii Croat & Grayum, in Croat, Ann. Missouri Bot. Gard. 84: 477. 1997. Long-stemmed trunk epiphytes, not usually appressed (attached by long, adventitious roots), fertile ca. 5-10 m above the ground. Cataphylls subpersistent, eventually deciduous intact. Petioles ca. 25-53 cm, flat or broadly convex above, rounded below, the margins obtuse to rounded. Leaf-blades 27-51 × 9-26 cm, lanceolate to narrowly ovate, rounded to cordate or subsagittate at base, with ca. 10-17 primary lateral veins per side. Infls. 1-3 per axil. Peduncles ca. 2-9 cm. Spathe tube red to purplish within. Spadix 11.5-17 × 1-1.8 cm. Ripe frs. orange (Pan.). Wet forests, 750-1300 m; Atl. slope Cords. Central (vic. Cariblanco) and Talamanca (vic. Moravia de Chirripó, Tapantí). Fl. Apr. Extr. SE Nic. to W cent. Pan., NW Ecua. (Lent 909, CR) Philodendron lentii, very rare in CR, is characterized by its long-stemmed habit, ± narrow leaf-blades rounded to shallowly cordate or subsagittate at the base and with many primary lateral veins, long, relatively short-pedunculate spadices, and apparently orange frs. It is perhaps most similar to P. davidsonii (see key, couplet 55), of the Atl. coastal plain. Philodendron ligulatum Schott, Prodr. syst. Aroid. 224. 1860. Long-stemmed, appressed-climbing trunk epiphytes or, eventually, loosely scandent vines, fertile to at least 2-3 m above the ground. Cataphylls deciduous intact. Petioles ca. 7-15.5(-26) cm, spongy, purplish distally, ± flattened above, rounded below, the margins rounded to acute. Leaf-blades ca. 25-37(-55) × 8-13.5(-18.1) cm, lanceolate to narrowly elliptical, oblong-lanceolate, or oblanceolate, rounded to auriculate at base, with ca. 8-13 primary lateral veins per side. Infls. solitary in axils. Peduncles 5-11.5 cm. Spathe tube deep reddish or purplish within. Spadix ca. 9.7-12.5 × 0.6-1.2 cm. Ripe frs. unknown. Wet forests, 0-650 m; entire Atl. slope. Fl. Apr.-Jul. NE Nic. to W Col. (Grayum 9823; CR, MO) Philodendron ligulatum is well marked by its long internodes, thick and markedly spongy petioles, ± narrow, non-cordate leaf-blades, and solitary, relatively long-pedunculate infls. It might be confused with either P. bakeri or P. wendlandii, with both of which it occurs sympatrically; the former sp. differs in having slender, firm petioles (see under P. bakeri for additional details), while the latter is distinct in its acaulescent, rosulate growth habit. CR material of P. ligulatum belongs to var. ligulatum, with roughly the same geographic range as the sp. Philodendron microstictum Standl. & L. O. Williams, Ceiba 3: 108. 1952. Appressed-climbing to ± loosely scandent epiphytes, fertile ca. 2.5-5 m above the ground. Cataphylls deciduous intact. Petioles ca. 11-23.5 cm, ± dorsiventrally compressed, flat to obscurely concave above, low-convex below, the margins rounded. Leaf-blades ca. 9.5-23.5 × 9.3-21.5 cm, reniform to broadly ovate, subcordate to cordate at base, with ca. 1-6 largely obscure primary lateral veins per side. Infls. solitary in axils. Peduncles ca. 13-24 cm. Spathe tube deep reddish within. Spadix ca. 7.5-13.7 × 0.4-1 cm. Ripe frs. unknown. Wet forests, 0-500 m; Pac. slope S from Puriscal region. Fl. Jan.-May, Aug. ENDEMIC. (Grayum et al. 7580; CR, MO) This ± common sp. of the Pac. lowlands is distinctive by virtue of its long internodes, smallish, ± cordate leaf-blades with obscure primary lateral veins, and long-pedunculate infls. It most closely resembles P. sulcicaule, of the Atl. lowlands (see key, couplet 52), but is more likely to be confused with the sympatric P. wilburii. The latter sp. differs from P. microstictum in its more deltate leaf-blades with conspicuous primary lateral veins, and shorter peduncles. Philodendron opacum Croat & Grayum, in Grayum, Phytologia 73: 35. 1992. P. karstenianum sensu Fl. Panama (pro parte), non Schott; P. nervosum sensu Fl. BCI, non Kunth. Appressed-climbing vines in understory, generally fertile 2-5 m above the ground, at least the juveniles often terrestrial. Cataphylls borne only among infls., (deciduous intact). Petioles 16.6-29.5(-35.2) cm, with largely erect sheath extending to within 3.5-10.7 cm of leaf-blade base. Leaf-blades 17.7-43.4 × 7.8-18.8 cm, narrowly to broadly ovate, lanceolate, elliptical, or oblong, or broadly oblanceolate, cuneate, rounded, or truncate at base (rarely obscurely subcordate), with 5-9 primary lateral veins per side. Infls. 1(2) in axils. Peduncles 3.7-5.8(-7.7) cm. Spathe tube pale green within. Spadix (5.2-)9.0-12.8(-14.8) × 0.80-1.45 cm. Ripe frs. translucent-whitish. Wet forests, 0-550 m; Atl. slope Cords. Guanacaste, Tilarán, and Central, Pac. slope S from R.B. Carara. Fl. Mar.-Jun., Aug.-Nov. Extreme SE Nic. to Pac. Ecua. (Grayum & Fleming 8120; CR, MO) Philodendron opacum is a spottily distributed, though locally abundant sp., characterized by its appressed-climbing habit, erect petiole sheaths extending ca. (55-)62-81% of the total petiole length, non-cordate leaf-blades usually matte or velvety above, and uniformly green spathes. The only CR sp. with which it might possibly be confused is P. standleyi, of higher elevations. The latter sp. differs from P. opacum in having glossier leaf-blades with more numerous primary lateral veins, and proportionately more slender spadices. This sp. is most frequent in ± disturbed habitats, including secondary forest, trail edges, and abandoned orchards. Philodendron platypetiolatum Madison, Selbyana 2: 22. 1977. Long-stemmed, ± loosely climbing epiphytic vines, usually fertile ca. 2-3 m above the ground. Cataphylls deciduous intact. Petioles ca. 15-56 cm, strongly flattened dorsiventrally (flat above, very shallowly convex below), the margins rounded. Leaf-blades ca. 21-39 × 15-30 cm, ovate or oblong-ovate, subcordate to cordate or (rarely) subsagittate at base, with ca. (6)7-11 primary lateral veins per side. Infls. 1 or 2 per axil. Peduncles ca. 7.5-18.5 cm. Spathe tube deep reddish to purplish within, and often externally as well (especially toward fr.). Spadix 9.5-15.5 × 0.5-0.8 cm. Ripe frs. unknown. Wet forests, 0-800(-1250?) m; Atl. slope Cords. Guanacaste, Tilarán, and Central (to R.N.F.S. Barra del Colorado and P.N. Tortuguero), S Pac. slope (very rare, vic. Golfito and head of Golfo Dulce). Fl. Jan., Aug.-Nov. NE Nic. to Pac. Ecua. (Burger & Baker 9890; CR, MO) The strongly flattened, ribbon-like petioles of this sp. are unique among CR Philodendron spp. It is further distinguished by its ± loosely scandent habit, usually cordate, reddish-drying leaf-blades, and relatively long-pedunculate spathes becoming reddish externally. Compare P. hederaceum and (especially) P. purpureoviride, the spp. with which P. platypetiolatum is most apt to be confused. This sp. is most frequently found along streams in primary forest. Philodendron popenoei Standl. & Steyerm., in Yunck., Field Mus. Nat. Hist., Bot. Ser. 9: 264. 1940. Terrestrial plants, sprawling and clambering over ground or atop boulders, or becoming scandent and ascending tree-trunks to at least 5 m above the ground. Cataphylls infrequent or inconspicuous, borne only among the infls. (deciduous intact). Petioles (20.9-)22.6-38.5(-44.7) cm, with erect to involute sheath extending to within 7.4-12.5(-17.4) cm of leaf-blade base. Leaf-blades (19.5-)26.7-36.6(-42.9) × (9.3-)17.6-32.3(-34.7) cm, broadly lanceolate to broadly ovate or suborbicular, rounded-cordate at base, with 8-15 primary lateral veins per side. Infls. (1)2 or 3 per axil. Peduncles (2.2-)3.6-5.3(-10.2) cm. Spathe tube uniformly cream-colored or pale greenish within. Spadix ca. 8.5-11.3 × 1-1.1 cm. Ripening frs. yellow-orange, yellow-brown, or orange-yellow. Wet forests, 0-650(-1000) m; Pac. slope S from R.B. Carara. Fl. Jun., Aug., Sep., Nov., Dec. E Guat. to NE Nic., CR and extreme W Pan. (Punta Burica). (Croat 67614; CR, MO) This is the only Philodendron sp. in CR with petiole sheaths narrowly clasping the stem (subg. Pteromischum) and cordate-based leaf-blades. The sheaths extend for (43-)53-72(-75)% of the total petiole length, rather short for subg. Pteromischum (but too long for subg. Philodendron). Philodendron popenoei is not confused with any other CR sp. Philodendron pterotum K. Koch & Augustin, in A. Braun et al., Append. gen. sp. Hort. berol. 1854 6. 1854-1855. P. mirificum Standl. & L. O. Williams. Robust, appressed-climbing trunk epiphytes, fertile ca. 2-10 m above the ground. Cataphylls persistent, weathering to brownish fibers. Petioles ca. 63-120 cm, shallowly convex or ± flattened above, rounded below, the margins divergently undulate-winged to base of blade. Leaf-blades ca. 45-115 × 34-86 cm, ovate, deeply cordate at base, with ca. 4-10 primary lateral veins per side. Infls. to 3-4+ per axil. Peduncles ca. 6-12 cm. Spathe tube deep red within, reddish to purplish externally. Spadix 11.1-19 × 1.2-1.6 cm. Ripe frs. unknown. Wet forests, 0-300(-700) m; N Atl. slope (Cords. Guanacaste and Central, Llanura de San Carlos), Pac. slope S from R.B. Carara, Isla del Caño. Fl. Feb., Mar., May, Jul. NE Nic. to E cent. Pan. (Grayum et al. 4066; CR, MO) The fully undulate-winged petioles of this sp. are unique among CR Philodendron. It is additionally distinguished by its very large size, glossy, cordate leaf-blades, and externally reddish spathe tubes. The only CR sp. with which P. pterotum could possibly be confused are P. dodsonii (which has subterete petioles) and the even more similar P. findens (see key, couplet 30). Philodendron purpureoviride Engl., Bot. Jahrb. Syst. 26: 526. 1899. High-climbing, loosely scandent vines, the fertile stems often pendent (but infls. erect). Cataphylls deciduous intact. Petioles 8-28 cm, ± spongy, terete or subterete (obscurely flattened above). Leaf-blades 10-30 × 5.5-19 cm, ovate or deltate, to lance-ovate or oblong-ovate, cordate at base, with 2-4(5) primary lateral veins per side. Infls. solitary in axils. Peduncles ca. 2-10.5 cm. Spathe tube deep reddish or purplish within, usually deep purplish externally. Spadix ca. 10.3-13.5 × 1.2-1.8 cm. Color of ripe frs. unknown. Wet forests, 0-1000(-1600+) m; Atl. slope Cord. Guanacaste, E Cord. Central (vic. Turrialba), Cord. Talamanca, Pac. slope S from R.B. Carara. Fl. Jan., Jul., Oct.-Dec. CR to Pac. Ecua. (Grayum & Herrera 9141; CR, MO) Philodendron purpureoviride, comprising loosely scandent plants with smallish, cordate leaf-blades, is extreme similar to the more common P. hederaceum (see key, couplet 66). It might also be confused with P. platypetiolatum, with which it shares externally red spathes, but the latter sp. has dorsiventrally flattened petioles. Philodendron radiatum Schott, Oesterr. Bot. Wochenbl. 3: 378. 1853. Massive, thick-stemmed, appressed-climbing trunk epiphytes, fertile ca. 1.5-10+ m above the ground (or fallen). Cataphylls persistent, weathering to brownish fibers. Petioles ca. 50-110+ cm, terete. Leaf-blades 48-136+ × 48-145+ cm, broadly ovate, deeply pinnately or (toward base) bipinnately lobed, cordate at base, with ca. 6 or 7 primary lateral veins per side. Infls. 1-5+ per axil. Peduncles ca. 3-13 cm. Spathe tube deep reddish to purplish within (and sometimes tinged reddish externally). Spadix ca. 11-23 × 1.5-2.4 cm. Ripe frs. white. Wet forests, 0-250 m; entire Atl. slope. Fl. Mar., May-Nov. Mex. (Quer., SLP) to E cent. Pan., and possibly N Col. (Davidse & Herrera 31512; CR, MO) Philodendron radiatum is unique among CR congeners by virtue of its deeply pinnately to bipinnately lobed leaf-blades. Compare, though, P. findens, the leaf-blades of which become once-pinnatifid by tearing. Because of its lobed leaf-blades, P. radiatum is often mistaken for a Monstera. CR material of P. radiatum belongs to var. radiatum, with the same geographic range as the sp. Philodendron rayanum Croat & Grayum, in Grayum, Syst. Bot. Monogr. 47: 131. 1996. Epiphytic vines climbing to at least 4 m above the ground. Cataphylls borne only below infls., red to purple-violet, deciduous intact. Petioles 5.8-17 cm, with spreading-erect to involute sheath extending to within 2.5 cm of leaf-blade base. Leaf-blades (10.7-)14.2-40.4(-42.3) × (3-)4.4-14.4(-22.7) cm, narrowly to broadly lanceolate or oblanceolate to elliptical, oblong or ovate, narrowly cuneate to subtruncate, rounded or subcordate at base, with 9-16 primary lateral veins per side. Infls. 1(2), terminal on the branches. Peduncles 1.3-3.5 cm. Spathe tube mostly whitish (with some red?) within. Spadix 7.8-12.5(-13.7) × 0.7-1.2 cm. Ripe frs. apparently yellow-orange. Wet forests, 0-1000+ m; Atl. slope Cords. Guanacaste (Volcán Tenorio) and Central (Volcán Barva), S Pac. slope (Golfo Dulce region). Fl. Apr.-Jun. CR to extr. E Pan. (Grayum 6930; INB, MO) Philodendron rayanum is a rare sp., characterized by its rigidly scandent habit, ± fully sheathed petioles, and usually narrow, non-cordate leaf-blades with numerous primary lateral veins. It is extremely similar to the much more common P. inaequilaterum (which see for distinguishing features), and might also be confused with either P. alliodorum (see key, couplet 16) or P. schottii (which see). Philodendron rhodoaxis G. S. Bunting, Acta Bot. Venez. 10: 308. 1975. Epiphytic vines, appressed-climbing on tree-trunks or over shrubs in forest understory, usually fertile 1.5-3.5 m above the ground. Cataphylls borne only among infls. (deciduous intact). Petioles 13.5-33.5 cm, with erect to involute sheath extending to within 4 cm of leaf-blade base. Leaf-blades (25.2-)27-56.2 × (5.7-)10-23.2(-25.2) cm, narrowly to broadly lanceolate or oblanceolate to (rarely) elliptical or obovate, cuneate to rounded or truncate at base (usually subcordulate at petiole apex), with 13-30+ primary lateral veins per side. Infls. (1)2(3) per axil. Peduncles 3.7-8.5(-11.2) cm. Spathe tube ± uniformly greenish cream to cream or yellowish green within. Spadix 8.7-15.3 × (0.6-)0.8-1.5 cm. Ripe frs. translucent-whitish. Wet forests, 0-1200 m; entire Atl. slope, Pac. slope S from R.B. Carara. Fl. Feb.-Nov. CR (and probably extreme SE Nic.) to Pac. Ecua., Ven. (Burger & Stolze 5558; CR, MO) Philodendron rhodoaxis, a common sp. in primary forest, is distinguished by its appressed-climbing habit, extensively sheathed petioles (with the ± erect sheath usually ending well short of the leaf-base on larger leaves), usually narrow, often oblanceolate leaf-blades, usually matte or velvety above, with numerous primary lateral veins, and uniformly greenish spathes. The spp. with which it is most likely to be confused are the much less common P. ensifolium and P. herbaceum, both restricted to the Atl. slope. See under those spp. for distinguishing features. Compare also P. standleyi (which see). CR material of Philodendron rhodoaxis belongs to subsp. lewisii Croat & Grayum (in Grayum, Syst. Bot. Monogr. 47: 106. 1996), which ranges S to Pac. Ecua. Philodendron rigidifolium K. Krause, in Engl. & K. Krause, Pflanzenr. IV.23Db (Heft 60): 7. 1913. P. guttiferum sensu Fl. BCI, Fl. Panama (pro parte), non Kunth. Much-branched, canopy lianas in primary forest, ascending to at least 30 m above the ground, occasionally descending to within 2 m of the ground on trees at forest edges or in pastures; long-pendent branches leafless, or with reduced leaves. Cataphylls lacking. Petioles (6.3-)7.2-13.2(-20.3) cm, with spreading-erect to involute sheath extending to within 2.6 cm of leaf-blade base, free distally and prolonged by (0.1-)0.7-2.3(-4.1) cm. Leaf-blades (12.3-)14.6-27.1 × (5.3-)6.7-18.7 cm, narrowly to broadly ovate, oblong, lanceolate or broadly elliptical, broadly cuneate (rarely) to truncate or (usually) rounded to subcordate at base (sometimes cordulate to cordate at petiole apex), subcoriaceous to coriaceous, with 5-8(9) primary lateral veins per side, the midrib usually paler than surface above (especially on juvenile and flagellar leaves). Infls. solitary, terminal on the branches. Peduncles 1.7-3.4 cm. Spathe tube uniformly greenish white to pale green within. Spadix (13-)15.6-24.6(-27+) × 0.6-1.35 cm. Ripe frs. apparently white. Wet forests, 0-450(-800) m; Atl. slope Cords. Central (to R.N.F.S. Barra del Colorado and P.N. Tortuguero) and Talamanca, S Pac. slope (head of Golfo Dulce). Fl. Mar.-Jun., Aug.-Dec. SE Nic. to extreme E Pan. (Grayum et al. 4120; CR, MO) Philodendron rigidifolium is distinctive in its canopy habit, extensively sheathed petioles with the sheath free distally, usually ± ovate to elliptic, coriaceous leaf-blades with the midrib paler than the surface above, and solitary, short-pedunculate, very long infls. This is the only sp. of subg. Pteromischum (with narrowly clasping petiole bases) that normally reaches the canopy. It might conceivably be confused with P. inaequilaterum, but the latter sp. has thinner (chartaceous) leaf-blades with much more numerous primary lateral veins. CR material of P. rigidifolium belongs to subsp. rigidifolium, with the same geographic range as the sp. Philodendron rojasianum Standl. & Steyerm., Publ. Field Mus. Nat. Hist., Bot. Ser. 23: 3. 1943. Rangy, branching, epiphytic vines, climbing to at least 2 m above the ground on trunks (or at least the younger plants sprawling on slopes or cliffs). Cataphylls lacking. Petioles 10-18 cm, with horizontally spreading sheath extending to within 2 cm of leaf-blade base, free distally and prolonged by (0.1-)0.6-1.6(-2.5) cm. Leaf-blades (11.6-)15.1-18.8(-20.5) × (3.7-)4.8-10.2(-13.6) cm, broadly or narrowly ovate to lanceolate, narrowly elliptical or (rarely) slightly obovate, broadly cuneate to truncate, rounded or subcordate at base, with 9-15(-17+) primary lateral veins per side. Infls. solitary, terminal on the branches. Peduncles 1.3-2.2 cm. Spathe tube pale green within. Spadix ca. 9.1-9.6 × 0.9-1.35 cm. Color of ripe frs. unknown. Wet forest, 1450 m; Pac. slope Cord. Talamanca (Cerro de la Muerte). Fl. Jan., May-Jul. (Guat.). S Mex. (Chis.) and Guat., CR. (Grayum et al. 9949; INB, MO) Philodendron rojasianum, known only from CR only by a single, sterile collection, is characterized by its branching, rigidly scandent habit, fully sheathed petioles with the sheath horizontally spreading, smallish, non-cordate leaf-blades with numerous primary lateral veins, and solitary infls., terminal on the branches. The only potentially sympatric sp. with which it might be confused is P. aurantiifolium (especially subsp. calderense); see the key (couplet 11) for distinguishing features. Compare also P. burgeri and P. tuerckheimii, which occur at lower elevations. The only known CR station for Philodendron rojasianum, along the Carretera Interamericana on the Valle de El General slope of Cerro de la Muerte, is a mere scrap of highly perturbed forest. Philodendron rothschuhianum (Engl.) Croat & Grayum, Ann. Missouri Bot. Gard. 74: 660. 1987. Syngonium rothschuhianum Engl., in Engl. & K. Krause, Pflanzenr. IV.23E (Heft 71): 124. 1920. More or less appressed-climbing trunk epiphytes, fertile ca. 1.5-3.5 m above the ground (rarely on the ground). Cataphylls deciduous intact. Petioles ca. 22.5-60 cm, ± spongy, terete or subterete. Leaf-blades ca. 17-41 × 21-50 cm, deeply trilobate with the lateral lobes usually ± weakly curved forward and medial lobe ca. (6.8-)8.2-21.3 cm wide, subcordate (rarely) to ± deeply cordate at base, with ca. 6-16(-20) primary lateral veins per side. Infls. 1-3 per axil. Peduncles 3.5-21 cm. Spathe tube ± uniformly greenish white within. Spadix ca. 7-14.5 × 0.9-1.6 cm. Ripe frs. greenish white. Wet forests, 0-900(-1450) m; entire Atl. slope and near Continental Divide. Fl. Jan.-Aug., Nov., Dec. E Hond. to W cent. Pan. (Gómez et al. 20320; CR, MO) Philodendron rothschuhianum is the only CR Philodendron sp. with trilobate leaf-blades that has the spathe tube uniformly greenish (with no trace of red) within. It is otherwise rather similar to P. tripartitum and, especially, P. cotobrusense (which see). Philodendron sagittifolium Liebm., Vidensk. Meddel. Dansk Naturhist. Foren. Kjøbenhavn 1849: 17. 1849. P. lancigerum Standl. & L. O. Williams. Usually ± appressed-climbing trunk epiphytes, fertile ca. 2-6 m above the ground, occasionally loosely scandent and ascending to canopy (rarely terrestrial or on rocks). Cataphylls deciduous intact. Petioles 14-65.5 cm, firm, ± swollen and purplish distally, shallowly convex to flattened or broadly channeled above, convex below, the margins rounded to acute. Leaf-blades ca. 24.5-63.5 × 9-32.5 cm, deltate, ovate or oblong-ovate to ± narrowly lanceolate or oblong-lanceolate, subtruncate to cordate, sagittate or subhastate at base, with (5)6-11 primary lateral veins per side, these usually darker than the surface below. Infls. 1-4 per axil. Peduncles 2.5-11 cm. Spathe tube (and sometimes much of blade) deep reddish or purplish within, and sometimes externally as well (at least toward margins). Spadix ca. 8-13.7 × 0.7-1(-1.2) cm. Ripe frs. white. Wet forests, 0-1400 m; Atl. slope Cords. Tilarán, Central (to P.N. Tortuguero) and Talamanca, Pac. slope S from R.B. Carara. Fl. Jan., Mar.-Nov. Mex. (Morelos, Ver.) to E Pan., Col., Ven. (Grayum 5624; CR, MO) Philodendron sagittifolium is a variable sp., characterized by its usually appressed-climbing habit, deciduous cataphylls, firm (rather than spongy) petioles with a purplish distal "geniculum", usually ± narrow, cordate or sagittate based leaf-blades with the main veins darker than the surface below, usually multiple infls. with the spathes purplish within, and white frs. Frequently, the petioles, peduncles, and external spathe surface are purplish-spotted. It is most likely to be confused with P. aromaticum (which see) and P. wilburii and allies (see key, couplet 69). Precociously flowering specimens of P. sagittifolium with smallish, truncate-based leaf-blades may approach P. bakeri (which see). Populations in the Pac. lowlands ("Philodendron lancigerum") tend to have unusually narrow leaf-blades, but do not otherwise differ. Some material from the Golfo Dulce region (e.g., Grayum & Hammel 10066, INB, MO), provisionally referred here, is very different in comprising canopy epiphytes with longer petioles, larger leaf-blades with more numerous primary lateral veins paler than the surface below, and longer, thicker spadices than usual. This may represent a different sp. The same is true of some sterile material from Isla del Coco (e.g., Foster 4177, F, MO), which has unusually prominulous tertiary veins on the adaxial leaf-blade surface. The application of the name Philodendron sagittifolium (based on a Mexican type) to CR material remains somewhat conjectural. Philodendron scalarinerve Croat & Grayum, in Croat, Ann. Missouri Bot. Gard. 84: 521. 1997. Appressed-climbing trunk epiphytes, fertile to at least 7 m above the ground. Cataphylls persistent, weathering to pale brownish fibers. Petioles ca. 34-62 cm, terete distally, shallowly concave above proximally, the margins rounded. Leaf-blades ca. 36-50 × 17-34 cm, ovate to lance-ovate or oblong-lanceolate, cordulate at base, with ca. 6-16 primary lateral veins per side, the tertiary veins prominulous on both surfaces. Infls. 1-4 per axil. Peduncles 16-21 cm. Spathe tube uniformly pale greenish within. Spadix ca. 10.5-14.5 × 0.7-1 cm. Ripe frs. whitish. Wet forests, 0-150 m; Atl. slope Cord. Central (to Boca Tapada and R.N.F.S. Barra del Colorado). Fl. Jan., Jun., Sep. CR (and possibly extreme SE Nic.) to Pac. Col. and possibly Ecua. (Grayum et al. 6147; CR, MO) This is a very distinctive sp. by virtue of its appressed-climbing habit, persistent cataphyll fibers, cordulate-based leaf-blades, and long-pedunculate infls. with the spathe tube uniformly greenish within. The only CR sp. it could possibly be confused with is the sympatric P. cretosum (see key, couplet 28). Philodendron scalarinerve is extremely rare and local in CR, where it is known from just three localities (Boca Tapada, Chilamate de Sarapiquí, and near Barra del Colorado). Philodendron schottianum H. Wendl. ex Schott, Oesterr. Bot. Z. 15: 72. 1865. Coarse, ± appressed-climbing trunk epiphytes, fertile ca. 3-5 m above the ground. Cataphylls persistent, weathering to light brown, fibrous reticulum with adhering pergamentaceous mats. Petioles ca. (48-)63-80+ cm, finely and uniformly whitish striate, ± flat above with a vague median ridge, rounded below, the margins obtuse to rounded. Leaf-blades ca. 39-80+ × 27.5-66 cm, broadly to ± narrowly ovate, deeply cordate at base, with ca. 6-10 primary lateral veins per side. Infls. ca. 1-3 per axil. Peduncles ca. 2.5-9 cm, with whitish, corky "lenticels" distally. Spathe tube deep reddish to purplish within, sometimes tinged dull reddish externally. Spadix ca. 9.4-13.7 × 1.3-2.7 cm. Ripe frs. whitish. Wet forests, 750-2100 m; Atl. slope and near Continental Divide, Cords. Tilarán, Central and Talamanca. Fl. Jan., Apr.-Aug. CR to E cent. Pan. (Cerro Jefe). (Grayum 7333; CR, MO) Philodendron schottianum is a montane sp., recognized by its appressed-climbing habit, fibrous cataphylls with adhering, parchment-like mats, large, cordate leaf-blades, reddish internal spathe surfaces, and proportionately thick spadices. It is most similar to the higher elevation P. alticola (see key, couplet 38), but is more likely to be confused with the sympatric P. thalassicum (which has more numerous primary lateral leaf veins, uniformly greenish spathes, and slenderer spadices). Philodendron schottii K. Koch, in Ender, Index aroid. 63. 1864. P. lingulatum sensu Schott (Syn. Aroid. 77. 1856), non (L.) K. Koch (1855). Coarse, loosely branching, scandent vines or lianas, climbing to at least 10 m above the ground. Cataphylls very infrequent, borne only below infls., (deciduous intact). Petioles (3.5-)5.2-18.8 cm, with erect to involute or (rarely) horizontally spreading sheath extending to within 1.1 cm of leaf-blade base, free distally and prolonged by up to 1.1 cm (often well beyond base of blade). Leaf-blades (11.7-)4.2-27.3 × (2.9-)3.7-12.3 cm, narrowly to broadly (often deltately) lanceolate to narrowly ovate or (rarely) oblanceolate, oblong or elliptical, cuneate to truncate or (more frequently) rounded and often cordulate at base, with ca. (6-)8-12 primary lateral veins per side, with brownish or blackish, interrupted resin canals conspicuous between veins in dried material. Infls. solitary, terminal on the branches. Peduncles ca. 0.6-1.5 cm. Spathe tube pale greenish or cream within, with many, finely parallel, longitudinal resin ducts externally when dried. Spadix ca. (5.8-)6.5-12.4 × 0.6-1.8 cm. Color of ripe frs. uncertain. Wet forests, 0-1000 m; entire Atl. slope, S Pac. slope (very rare; head of Golfo Dulce). Fl. Jan., Feb., Apr.-Oct., Dec. Mex. (Oax., Ver.) to E cent. Pan., S Pac. Col. and N Pac. Ecua., Jam. (Grayum & Sleeper 6538; CR, MO) Philodendron schottii comprises branching, rigidly scandent plants with extensively sheathed petioles (with the sheath usually involute and free distally), smallish, usually narrow, non-cordate leaf-blades, and solitary infls. with proportionately thick spadices. In life, it is most apt to be confused with P. inaequilaterum, but the latter sp. has generally larger and proportionally broader leaf-blades with more numerous primary lateral veins, as well as longer, more slender infls. It might also confused with P. alliodorum or the very rare P. rayanum (see key, couplet 15). Herbarium specimens of P. schottii are distinct from those of all the above sp., since the dark resin canals in the leaf-blades and on the exterior spathe surface are more evident. CR material of P. schottii belongs to subsp. talamancae (Engl.) Grayum (Syst. Bot. Monogr. 47: 142. 1996; P. talamancae Engl., Bot. Jahrb. Syst. 26: 511. 1899), which accounts for the entire geographic range of the sp. except for Jam. Philodendron squamicaule Croat & Grayum, in Croat, Ann. Missouri Bot. Gard. 84: 529. 1997. Appressed-climbing trunk epiphytes, the stems covered with narrowly triangular, multiseriate scales. Cataphylls covered with linear, cirrhous scales, persistent, weathering to a reticulum of reddish brown fibers. Petioles ca. 29.5-92 cm, terete or subterete, reddish or purplish, densely covered with ± spreading, tortuous, pale green, hair-like scales to ca. 5 mm long. Leaf-blades ca. 28-62 × 21.5-40 cm, deltate or ovate, ± deeply cordate at base, with ca. 7-14 primary lateral veins per side, these and midrib densely and minutely granular-pubescent below, the posterior ribs covered with small scales. Infls. 1-3 per axil. Peduncles ca. 8-17.5 cm, densely covered with pale green, hair-like scales. Spathe tube reddish to purplish within (and sometimes so tinged externally), the entire spathe scaly as peduncle externally. Spadix ca. 10.9-17.5 × 0.7-1.2 cm. Ripe frs. unknown. Wet forests, 450-750 m; Atl. slope Cord. Central (Volcán Barva). Fl. Jul. (Pan.). SE Nic. to W cent. Pan., Pac. Col. (Grayum & Sleeper 6523; INB, MO) This and the much more common P. verrucosum are the only two CR Philodendron spp. that have the stems, petioles, peduncles, and spathes covered with hair-like processes. See the key (couplet 25) for distinguishing features. Philodendron squamicaule is very rare in CR, where it has only been collected in sterile condition. Philodendron standleyi Grayum, Phytologia 73: 37. 1992. Appressed-climbing trunk epiphytes (juveniles may grow more loosely over shrubs, rocks or banks), climbing to at least 10 m above the ground (usually fertile at least 2.5 m above the ground). Cataphylls borne only among infls. (deciduous intact). Petioles (13.6-)18.9-37.8(-42) cm, with involute to erect or (distally) horizontally spreading sheath extending to within (0.9-)2-4.6(-7.1) cm of leaf-blade base. Leaf-blades (17.6-)22.1-40.3(-54.8) × (7.3-)10.3-21.5(-27.2) cm, ovate to broadly lanceolate, narrowly to broadly elliptical or (very rarely) obovate, cuneate to rounded, truncate or (less frequently) subauriculate or subcordate at base (and often cordulate at the petiole apex), with (5-)8-15(-21) primary lateral veins per side. Infls. 1 or 2 per in axils. Peduncles (2.3-)3.4-7.1(-8.6) cm. Spathe tube greenish white within. Spadix 9-15.3(-16.9) × (0.5-)0.8-1(-1.2) cm. Color of ripe frs. uncertain. Wet forests, 700-1750 m; Atl. slope and near Continental Divide, Cords. Tilarán, Central, and Talamanca, Pac. slope Cord. Talamanca, Fila Costeña. Fl. Jan.-Aug., Dec. Mex. (Ver.) to W cent. Pan. (Grayum et al. 8110; INB, MO) Philodendron standleyi is recognized by its appressed-climbing habit, petioles with ± erect sheaths extending for ca. (75-)81-97% of their total length (with the unsheathed portion 2 cm or more long on at least some larger leaves), and non-cordate leaf-blades ± glossy above. It is most similar to P. opacum (which see), of lower elevations, but more likely to be confused with the sympatric P. rhodoaxis. The latter sp. differs in its persistently green stems and more inequilateral leaf-blades, matte to velvety above, with more numerous primary lateral veins. Philodendron straminicaule Croat, Ann. Missouri Bot. Gard. 84: 532. 1997. Trunk epiphytes. Cataphylls deciduous intact. Petioles ca. 20-40.5 cm (appearing spongy and terete). Leaf-blades 21.5-33 × 11.5-22.5 cm, narrowly deltate to lance-deltate, deeply cordate or subsagittate to subhastate at base, with ca. 5-8 primary lateral veins per side. Infls. 1 or 2 per axil. Peduncles ca. 5.8-12.5 cm. Spathe tube reddish violet to maroon or magenta within (Pan.). Spadix ca. 7-11.6 × 0.8-1 cm. Ripe frs. greenish white to lavender (Pan.). Wet forests, 1100-1400 m; Cord. Guanacaste (Volcanes Cacao y Rincón de la Vieja). Fl. Jan., Jul., Sep. CR to W cent. Pan., Pac. Col. (II INBio 219; INB, MO) Philodendron straminicaule is extremely similar to P. wilburii, from which fr. color would appear to be the chief distinction (see key, couplet 71). The above description is based strictly on CR collections (except as noted) determined by Croat. Because fr. color is not known for any of the CR specimens, their identification must be regarded as tentative. Indeed, the distinctness of the sp. is also open to question. Philodendron strictum G. S. Bunting, Phytologia 60: 328. 1986. Terrestrial on steep banks or (less often) appressed-epiphytic on trunks. Cataphylls ± persistent, gradually deliquescing and leaving some basal fibers. Petioles ca. 52-105 cm, subterete (± flat above distally, ± sulcate proximally, the margins ± rounded), drying yellowish and cracking. Leaf-blades ca. 27-62 × 18-43 cm, ± broadly ovate, deeply and narrowly cordate at base, whitish and matte below, with ca. 7-12 primary lateral veins per side. Infls. 1-3 per axil. Peduncles 6-12 cm. Spathe tube deep reddish or purplish within, and sometimes externally. Spadix ca. 10-16.5 × 1.3-1.8 cm. Ripe frs. white. Wet forests, 650-1275 m; Atl. slope Cords. Central and Talamanca, S Pac. slope (Fila Costeña). Fl. Feb., Jul., Aug. CR to W cent. Pan., W Col., N Ecua., SW Ven. (I. Chacón 9; CR, MO) Philodendron strictum is one of only three CR Philodendron spp. that are characteristically terrestrial (cf. also P. grandipes, P. thalassicum). It is most similar to P. thalassicum, with which it has been confused in the past, but differs in its yellowish-drying petioles and reddish or purplish (rather than uniformly green) inner spathe-tube coloration. Philodendron sulcatum K. Krause, in Engl. & K. Krause, Pflanzenr. IV.23Db (Heft 60): 19. 1913. Appressed-climbing, understory trunk epiphytes, fertile to 1.5-4 m above the ground. Cataphylls borne only among infls. (deciduous intact). Petioles ca. 8-17.5(-21.6) cm, with erect to (usually) horizontally spreading sheath extending to within 1.8 cm of leaf-blade base. Leaf-blades ca. 14.3-28 × 4.1-12.8 cm, ovate to narrowly or broadly elliptical to lanceolate, cuneate or rounded (rarely truncate to subcordate) at base, with ca. 5-11 primary lateral veins per side. Infls. 1 or 2 (3?) per axil. Peduncles 3.1-9(-11.7) cm. Spathe tube pale green or cream within. Spadix 7.6-12.6(-13+) × 0.5-0.85(-0.95) cm. Ripe frs. apparently whitish. Wet forests, 0-1000 m; entire Atl. slope, Pac. slope S from R.B. Carara. Fl. Jan., Feb., Apr.-Aug., Dec. N cent. Nic. to Pac. Ecua. (Croat 36453; CR, MO) This is the only CR Philodendron sp. with extensive, horizontally spreading petioles sheaths and smallish leaves that has (at least potentially) two infls. per axil and produces cataphylls. In vegetative condition, it might be confused with P. aurantiifolium, P. burgeri, P. rojasianum, or P. tuerckheimii; however, those sp. comprise more extensively branching, loosely scandent, "shrubby" plants. Philodendron sulcatum is often found in somewhat disturbed sites, such as trail edges, secondary forest, or abandoned plantations. Philodendron sulcicaule Croat & Grayum, in Croat, Ann. Missouri Bot. Gard. 84: 537. 1997. Loosely scandent epiphytic vines, potentially climbing into canopy (occasionally on the ground), the internodes prominently ribbed and sulcate. Cataphylls deciduous intact. Petioles ca. 5.5-20 cm, subterete (weakly flattened above). Leaf-blades 6.5-24 × 5.5-15.5 cm, broadly ovate or deltate to oblong-lanceolate, subcordate to cordate or subsagittate at base, with primary lateral veins not or scarcely evident. Infls. 1-5 per axil. Peduncles ca. 4-10 cm. Spathe tube pink to red or purplish within. Spadix ca. 4.4-8.2 × 0.2-0.5 cm. Ripe frs. unknown. Wet forests, 100-250 m; Atl. slope Cord. Talamanca (vic. Bribrí). Fl. May. CR to E Pan. (Gómez et al. 20473, MO) Philodendron sulcicaule, restricted in CR to the Sixaola region, is well marked by its prominently sulcate stems, smallish, cordate leaf-blades with obscure primary lateral veins, numerous (to at least 5) infls. per axil, and very small, slender spadices. The infls. are the smallest of any CR Philodendron. The only similar CR sp. is P. microstictum, of the Pac. lowlands (see key, couplet 52). Philodendron tenue K. Koch & Augustin, in A. Braun et al., Append. gen. sp. Hort. berol. 1854 7. 1854-1855. P. gracile Schott. Appressed-climbing trunk epiphytes, fertile ca. 1.5-4 m above the ground. Cataphylls persistent, weathering to reddish brown fibers. Petioles 26.5-107 cm, terete or subterete, finely pluricostate. Leaf-blades ca. 32-86 × 15-48 cm, deeply hastately trilobate (with the medial lobe ca. 12.5-34 cm wide) to lance-ovate, lance-deltate, pandurate or oblong-lanceolate, ± deeply cordate to (more frequently) sagittate or hastate at base, with ca. 10-20 primary lateral veins per side. Infls. 1-5 per axil. Peduncles 2-6 cm. Spathe tube deep reddish or purplish within, and usually externally as well. Spadix ca. 6-9.9 × 0.7-1.2 cm. Ripe frs. white. Wet forests, 0-800(-1000) m; Atl. slope (and near Continental Divide) Cords. Guanacaste, Tilarán, Central (to R.N.F.S. Barra del Colorado), and N Cord. Talamanca, S Pac. slope (Golfo Dulce region and Osa Pen.). Fl. Jan.-Aug. E Hond. to Pac. Ecua., N and W Ven. (Herrera 4013; CR, MO) Philodendron tenue is readily distinguished by its appressed-climbing habit, reddish cataphyll fibers, terete petioles, usually sagittate or hastate leaf-blades, and smallish infls. with the spathe tube usually reddish on both surfaces. The CR spp. with which it is most likely to be confused are P. fragrantissimum and P. thalassicum (see under those entries). Philodendron thalassicum Croat & Grayum, in Croat, Ann. Missouri Bot. Gard. 84: 541. 1997. Terrestrial with stout, decumbent to erect stems, or appressed-climbing on trunks and fertile to ca. 4 m above the ground. Cataphylls persistent, greenish or reddish, ultimately weathering to a reticulum of whitish or brownish fibers. Petioles ca. 40.5-109 cm, usually finely striate, subterete to ± D-shaped (usually flattened above often with a low median keel distally, rounded below, the margins obtuse to rounded). Leaf-blades ca. 38-77 × 22.5-52 cm, ± broadly to narrowly ovate or deltate to lance-deltate, deeply cordate to sagittate at base, sometimes ± velvety above, much paler (± glaucous) and usually matte below, with ca. 8-14 primary lateral veins per side. Infls. 1-3+ per axil. Peduncles 3.5-16 cm, ± prominently whitish- or pinkish-striate distally. Spathe tube uniformly pale green or whitish within. Spadix 7.2-18.4 × 0.7-1.4 cm. Ripe frs. white. Wet (often oak) forests, ca. 1000-2100 m; Atl. slope and near Continental Divide, Cords. Tilarán and Central, both slopes Cord. Talamanca, Tablazo. Fl. Jan.-Dec. CR and extreme W Pan. (Grayum & Schatz 5181; CR, MO) Philodendron thalassicum is a variable sp., characterized by persistent cataphyll fibers, large, cordate to sagittate leaf-blades whitish below, and spathe tubes uniformly greenish or whitish within. As here construed, it is one of very few CR Philodendron sp. that may be either terrestrial or epiphytic (cf. also P. strictum). Terrestrial plants (including the specimen cited above) always have broadly ovate-cordate leaf-blades, while epiphytic specimens (Grayum 11020; CR, INB, MO) often have narrower (sagittate) blades. However, there seem to be no consistent morphological differences between the two growth forms, and many collections with broadly ovate-cordate blades are reported as epiphytic. Specimens of Philodendron thalassicum with ovate-cordate leaf-blades are most apt to be confused with P. schottianum or P. strictum (which see), while sagittate-leaved, epiphytic specimens approach P. tenue (which has concolorous leaf-blades and smaller infls. with the spathe tube reddish on both surfaces). Philodendron tripartitum (Jacq.) Schott, Wiener Z. Kunst 1829: 780. 1829. Arum tripartitum Jacq., Pl. hort. schoenbr. 2: 33, pl. 190. 1797. Epiphytic vines, ± appressed to loosely scandent, fertile to at least 1.5 m above the ground. Cataphylls deciduous intact. Petioles 26-67(-71) cm, ± spongy, terete or subterete. Leaf-blades (15.5-)22-45(-49) × 21-43(-46) cm, trifoliolate or very deeply trilobate with the lateral lobes curved forward and medial lobe (3.5-)5-14 (-19) cm wide, cordate to subcordate or rounded at base, with 5-17 primary lateral veins per side. Infls. 1 or 2(3?) per axil. Peduncles 4-14.5 cm. Spathe tube pink to reddish or deep purplish within in basal half. Spadix ca. 9-16.5 × 0.8-1.6 cm. Ripe frs. whitish. Wet forests, 0-1500+ m; entire Atl. slope and near Continental Divide, Pac. slope S from R.F. Los Santos. Fl. Jan.-Sep., Nov. Mex. (Oax., Ver.) to Pac. Col., Jam. (Grayum 6979; CR, MO) Philodendron tripartitum is the most widespread and commonly collected of the CR Philodendron spp. with tripartite leaf-blades. It is recognized by its comparatively deeply lobed leaf-blades with numerous primary lateral veins, spathe tubes reddish within, spadices as long or longer than the peduncles, and whitish frs. The CR sp. with which it is most likely to be confused is the dubiously distinct P. cotobrusense (see key, couplet 23). Pac. slope collections of P. tripartitum tend to approach P. cotobrusense in having comparatively large leaf-blades (with wider medial lobes with a higher average number of primary lateral veins), with the lobes more broadly confluent at the base, as well as more numerous infls. (often 2 or 3 per axil). Philodendron tuerckheimii Grayum, Syst. Bot. Monogr. 47: 174. 1996. Much-branched, rigidly scandent vines climbing on trunks or in understory vegetation to 6(-10?) m above the ground, with dark, wiry stems. Cataphylls lacking. Petioles ca. 3.5-7.9 cm, with broadly horizontally spreading sheath extending to within 0.5 cm of leaf-blade base. Leaf-blades ca. 7.9-15.2 × (2.5-)3-10 cm, broadly (rarely narrowly) lanceolate to ovate, deltate, or broadly to narrowly elliptical or oblong, cuneate or rounded to truncate or cordulate at base, with ca. 5-7 primary lateral veins per side. Infls. solitary, terminal on the branches. Peduncles (0.8-)1.1-2.2 cm. Spathe tube pale green to whitish within. Spadix 6.1-9 × 0.45-0.8 cm. Color of ripe frs. unknown. Wet forests, 200-1100 m; Atl. slope Cords. Guanacaste, Tilarán, Central, and N Cord. Talamanca, S Pac. slope (near Golfito). Fl. May., Sep. Mex. (Oax., Ver.) to Pac. Ecua. and W Ven. (Liesner & Judziewicz 14939; CR, MO) Philodendron tuerckheimii is an inconspicuous and apparently rare (though widespread) sp. in CR, where it is known from just six collections. It is characterized by its branching habit, short (ca. 50% of the blade length) petioles with broadly splayed sheaths, smallish, reddish-brown-drying leaf-blades with few (5-7 pairs) primary lateral veins, and solitary infls. with a relatively long female portion. The only spp. with which it is likely to be confused are P. aurantiifolium and P. rojasianum (with longer petioles and more numerous primary lateral veins) and the Pac. slope P. burgeri (see key, couplet 12). Philodendron verrucosum L. Mathieu ex Schott, Syn. Aroid. 85. 1856. More or less appressed-climbing trunk epiphytes, fertile to at least 4.5 m above the ground or creeping on ground, the stems ± densely covered with semicircular to broadly triangular, multiseriate scales often in ± transverse lines. Cataphylls ± densely covered with broad-based, cirrhous scales, persistent, becoming translucent and ultimately weathering to a fibrous reticulum. Petioles ca. 35-70 cm, terete or subterete, reddish or purplish, densely covered with ± spreading or retrorse, tortuous, fleshy, whitish to pale green, hair-like scales to ca. 9 mm long. Leaf-blades ca. 36-67 × 28-52 cm, subrotund to deltate, deeply cordate at base, velvety and dark green becoming medium green above, matte and purplish becoming whitish or pale green below (with main veins much darker), with ca. 5-8 primary lateral veins per side, these and midrib minutely granular-pubescent below, the posterior ribs scaly as petioles. Infls. 1-4 per axil. Peduncles ca. 9.5-23 cm, densely covered with whitish or pale green, fleshy, hair-like scales. Spathe tube deep reddish or purplish within, often tinged dull reddish externally, the entire spathe scaly as peduncle externally. Spadix ca. 10-16.5 × 0.9-1.8 cm. Ripe frs. whitish. Wet forests, 200-1500 m; Atl. slope and near Continental Divide, Cords. Tilarán, Central, and Talamanca, S Pac. slope (Fila Costeña). Fl. Jan., Apr.-Jul., Oct., Nov. CR to Pac. Ecua., Amaz. Ecua. and Perú. (Grayum 5621; CR, MO) Philodendron verrucosum is a familiar sp., well marked by the fleshy, hair-like protuberances covering its stems, petioles, peduncles, and external spathe surfaces, as well as its large, cordate, purplish-stained leaf-blades. The only CR sp. with which it could possibly be confused is the very similar, though rare, P. squamicaule (see key, couplet 25). Philodendron wendlandii Schott, Prodr. syst. Aroid. 221. 1860. Short-stemmed (acaulescent), rosette-forming epiphytes, fertile ca. 2.5-5 m above the ground or in the canopy, or on stumps or logs (sometimes found on the ground). Cataphylls deciduous intact. Petioles ca. 10-25 cm, markedly spongy and swollen, broadly and shallowly concave to flattened above, convex below, the margins acute. Leaf-blades ca. 32-68.5 × 8.5-20 cm, ± narrowly elliptical to oblanceolate or spatulate, cuneate to rounded, truncate, or subauriculate at base, with ca. 11-18 primary lateral veins per side. Infls. 1-3 per axil. Peduncles ca. 3-11 cm. Spathe tube deep reddish or purplish within. Spadix ca. 12.5-17.5 × 0.9-1.4 cm. Ripe frs. bright orange. Wet forests, 0-700(-1250) m; entire Atl. slope. Fl. Feb.-Jul., Nov. SE Nic. to E cent. Pan. (Herrera 2993; CR, MO) Philodendron wendlandii is easily recognized by its rosulate habit, markedly spongy petioles, narrow, non-cordate leaf-blades, and bright orange frs. It is most similar to the Pac. slope P. auriculatum (see key, couplet 43), but perhaps more likely to be confused with the sympatric P. ligulatum (comprising scandent plants with long internodes). Pan. material of P. wendlandii differs ± consistently in having the petiole margins more sharply winged and the spathe tube whitish to pale green (rather than reddish or purplish) within. The name Philodendron wendlandii is used in a wholly different sense in Fl. Panama, i.e., mainly for the sp. now known as P. immixtum Croat. This sp. is well known in the worldwide horticultural trade ("Bird's Nest Philodendron"), and is often cult. in CR as a patio ornamental. Philodendron wilburii Croat & Grayum, in Croat, Ann. Missouri Bot. Gard. 84: 559. 1997. Appressed-climbing or ± loosely scandent vines (rarely on the ground), usually fertile ca. 2-5 m above the ground. Cataphylls deciduous intact. Petioles 12-48 cm, ± spongy to firm, subterete, ± flattened to obscurely sulcate above especially distally, the margins obtuse to rounded. Leaf-blades 12-39 × 6-25.5 cm, deltate or oblong-deltate to lance-deltate, shallowly to ± deeply cordate to sagittate or subhastate at base, often tinged reddish or purplish especially along the major veins below, with ca. 3-8 primary lateral veins per side. Infls. 1-3 per axil. Peduncles 4.5-15.5 cm. Spathe tube pinkish to reddish or purplish within. Spadix ca. (5.1-)6.1-11.1(-12.9) × (0.5-)0.6-1.4 cm, often drying orangish. Ripe frs. bright orange. Wet forests, 0-2000 m; Atl. slope and near Continental Divide (750-2000 m), Cords. Tilarán, Central and Talamanca, Cerro Azahar, Pac. slope (0-1150 m) S from R.B. Carara. Fl. Jan., Feb., Apr.-Dec. CR to E Pan. (Grayum & Sleeper 6116; CR, MO) Philodendron wilburii is characterized by its slender, usually easily compressible, subterete petioles, smallish, ± triangular, cordate- or sagittate-based leaf-blades, relatively long-pedunculate infls., and bright orange frs. It is most easily confused with the dubiously distinct P. cotonense and P. straminicaule (see key, couplets 70 and 71). Philodendron wilburii is not definitely known from the Cord. Guanacaste (where it is replaced by the essentially identical P. straminicaule), or from below 750 on the Atl. slope. Material from the Pac. lowlands (Grayum et al. 4759, CR, MO), representing var. longipedunculatum Croat & Grayum (in Croat, Ann. Missouri Bot. Gard. 84: 563. 1997), tends to have firm (rather than ± spongy) petioles, leaf-blades drying brownish, generally longer peduncles, and longitudinally ribbed or costate spathes. The remainder of the geographic range of the sp. in CR is occupied by var. wilburii, which extends only to W Pan. Grayum 5418 (CR, MO), from 1300 m on the Pac. slope of the Cord. Tilarán at Monteverde, has prominently hastately lobed leaf-blades and may be this or some other sp., e.g., P. mexicanum Engl. TOP