BFNA Title: Fossombroniaceae
Date: Dec. 15, 2019
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Bryophyte Flora of North America, Provisional Publication
Missouri Botanical Garden
BFNA Web site: http://www.mobot.org/plantscience/BFNA/bfnamenu.htm

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XX.  FOSSOMBRONIACEAE Hazlinszky, nom. cons.

Barbara Crandall-Stotler

James R. Bray, Jr.

Plants dissected thalloid (leafy in appearance), comprised of a fleshy stem and 2 ranks of delicate, lateral, succubously inserted leaves, simple or furcately branched, pale to bright green, occasionally with reddish brown secondary pigments. Stems dorsally compressed, without a defined ventral mycorrhizal zone; central strand absent; ventral surface with 2 rows of ventral appendages; rhizoids reddish purple or violet (rarely hyaline). Leaves succubous to almost longitudinal, contiguous to imbricate, rarely distant, 2--4-stratose at the base, becoming unistratose distally. Gametangia dispersed on the dorsal side of the stem; antheridia naked, or subtended singly by a perigonial scale; archegonia naked. Sporophytes enclosed in a thin shoot calyptra and an either free or fused caulocalyx; Sporophytes emergent to long emergent; capsules spheroidal or rarely obovoidal to ellipsoidal, nonvalvate, dehiscence irregular; capsule wall 2-stratose or rarely 3(--4)-stratose; outer wall cells hyaline, without thickenings.

Genera 1: cosmopolitan, with diversity "hotspots" in South Africa and Australia

With the segregation of Petalophyllum and Sewardiella into the Petalophyllaceae (B. Crandall-Stotler et al. 2002) and the recognition of Austrofossombronia as a synonym of Fossombronia (B. Crandall-Stotler et al. 2009), Fossombroniaceae are now considered a monogeneric family (L. Söderström et al. 2016). The family is phylogenetically most closely related to the Petalophyllaceae and the New Zealand endemic Allisoniaceae (L. L. Forrest and B. Crandall-Stotler 2004).

SELECTED REFERENCES  Crandall-Stotler, B. J., R. E. Stotler & C. Heather Ford. 2002.   Contributions toward a monograph of Petalophyllum (Marchantiophyta). Novon 12: 334--337.   Crandall-Stotler, B., R. E. Stotler & D. G. Long. 2009. Phylogeny and classification of the Marchantiophyta. Edinburgh J. Bot. 66: 155--198.   Forrest, L. L. & B. J. Crandall-Stotler. 2004. A phylogeny of the simple thalloid liverworts (Jungermanniopsida, Metzgeriidae) as inferred from five chloroplast genes. In: Goffinet, B., V. Hollowell and R. Magill, eds. Molecular Systematics of Bryophytes, pp. 119--140. St. Louis: Missouri Botanical Garden Press.   Söderström, L., A. Hagborg, M. von Konrat et al. 2016. World checklist of hornworts and liverworts. PhytoKeys 59: 1--828.

1. FOSSOMBRONIA Raddi, Jungermannniogr. Etrusca, 29. 1818 *( [For Vittorio Fossombroni, statesman and mathematician of Florence]

Plants small to robust, prostrate, ascending or erect, forming rosettes, turfs or mats over soil or rocks, occasionally emergent in wetlands. Leaves erect, patent, or nearly horizontal, crispate to undulate, or plane, quadrate to oblate, or oblong-rectangular with the apices truncate to rounded, and the margins entire, dentate, or shallowly lobed; median leaf cells large, elongate to isodiametric, with uniformly thin walls; trigones inconspicuous; oil bodies up to 80 per cell, small, homogeneous, glistening. Ventral appendages either small scales, 1-seriate hairs, or stalked papillae. Tubers absent or present, when present, from stem apex or ventral side of stem. Monoicous or dioicous. Antheridia clustered or scattered on dorsal side of the stem, hyaline or pale yellow at maturity; stalk 4--5(--9)-seriate. Archegonia clustered on dorsal side of the stem, near the apex, rarely scattered. Caulocalyces 1--4 per shoot, height less than, greater than, or equal to plant width, tubular to campanulate, sessile to conspicuously stipitate, with the surface smooth, or ornamented with either rounded ribs or foliar lamellae; mouth erect, incurved or recurved, entire, or lobed, with the margins entire to dentate. Spores trilete (polar), or cryptopolar, rarely apolar (F. angulosa), small to large, yellowish-brown to deep brown or deep purplish-red, disassociated when mature, rarely remaining in tetrads; the distal surface areolate, reticulate, lamellate, cristate or echinate; the proximal surface verrucate, cristate or lamellate; the proximal triradiate ridge absent, incomplete or distinct; the equatorial wing absent or distinct. Elaters few or abundant, short and stout or elongate, 10--400 µm long, 5.7--19.3 µm wide, unbranched or branched, with 1--6 spirally twisted thickening bands, with the spirals loosely, moderately or tightly coiled; the spiral bands yellowish brown to strong brown or deep purplish-red, with the elater surface smooth or granular. 

Species: 80--100 (11 in the flora); cosmopolitan on soil or over rocks, never epiphytic.

Fossombronia is one of the few "leafy" members of the simple thalloid subclass Pelliidae (B. Crandall-Stotler et al. 2009). Many species are perennials, forming either thickened stem apices or tubers that re-new shoot growth in situ, but some species appear to be short-lived annuals, with new shoot systems coming only from spores. Plant leaves are succubously inserted, undivided and often wider than long (=oblate), with crispate to undulate margins, and are always multistratose at the base, up to one-third of leaf length. The ventral surface of the stem is densely covered with purple to dark red-violet rhizoids that obscure 2 rows of ventral scales, 1-seriate hairs, or simple slime papillae. One of the most distinctive characters of the plants, which immediately distinguish them from true leafy hepatics (i.e., Jungermanniidae) is the scattered, usually naked gametangia along the dorsal surface of the stem. Most species are monoicous, either with antheridia and archegonia intermixed, or with antheridia produced well in advance of archegonia (protandry). When protandrous, only archegonia may be visible at the time of sporophyte maturation and such plants may be mistakenly identified as being dioicous. Repeated sampling of a population through the growing season is essential to differentiate truly dioicous species, e.g., F. marshii, from monoicous, protandrous ones, e.g., F. foveolata (R. E. Stotler et al. 2010).

Sporophytes are commonly present on the dorsal surface of the stem just posterior to the shoot apex. Each sporophyte is enclosed by an archegonium-derived calyptra and stem-derived structure termed a caulocalyx (Chalaud 1928: 182). This latter structure, which develops only after fertilization, has sometimes been referred to as a perianth (J. A. Paton 1999) or pseudoperianth (R. M. Schuster 1992), but is not homologous to either of these structures (see G. Chalaud 1928 and B. Crandall-Stotler et al. 2002 for further discussion). The caulocalyx often consists of a basal fleshy stalk or stipe of variable length and an upper, unistratose foliar calyx. Variations that occur in the level of stipe development and calyx morphology are diagnostic species level characters. The sporophyte itself varies little among species, but allows for easy identification of the genus. Capsules are dark brown to black, spheroidal (ovoidal in a few species, e.g., F. incurva in our flora) and non-valvate, breaking apart irregularly during dehiscence. Spores vary in size, shape and ornamentation among species, and have been heavily relied upon for species level identifications. Although distinctive spore characters can help differentiate species with fairly similar gametophyte morphologies, spore characters alone are not reliable indicators of taxonomic identity since taxa with different gametophyte morphologies can have fairly similar spores, e.g., F. porphyrorhiza, F. salina, and F. foveolata. Unfortunately, this over-reliance on spore characters has frequently blurred the recognition of species and resulted in inappropriate synonymies. Expanded discussions of such synonymies and the changing views of species recognition have been submitted to the on-line journal Phytoneuron (www.phytoneuron.net).

Most of our species occur on small pockets of exposed soil in fields, along paths or roadways, or over rocky ledges, often in seasonally dry habitats, but they may also grow over rocks or soil near streams, or swampy areas. Sporophytes are likely to be most abundant in the spring and/or fall, when moisture is available. Common associates include various species of Riccia and Asterella, as well as Pellia epiphylla, Phaeoceros carolinianus, and small, ephemeral mosses.  

SELECTED REFERENCES  Chalaud, G. 1928. Le cycle évolutif de Fossombronia pusilla Dum. Librairies Générale de L'Enseignement, Paris.  Crandall-Stotler, B. J., R. E. Stotler & C. H. Ford. 2002. Contributions toward a monograph of Petalophyllum (Marchantiophyta). Novon 12: 334--337.   Paton, J. A. 1999. The Liverwort Flora of the British Isles. Colchester, England.  Schuster, R. M. 1992. The Hepaticae and Anthocerotae of North America, Vol. V. Field Museum, Chicago. 854 pp.   Stotler R. E., B. J. Crandall-Stotler and J. R. Bray, Jr. 2010. Fossombronia marshii (Marchantiophyta), a new liverwort species from Arkansas. Phytologia 92: 230--232.

1.  Plants ascending to erect, arising from a subterranean, rhizome-like axis; leaves oblique to almost transverse, erect, crispate, oblate to subquadrate, with apices 3--5-lobed; spores less than 25 /um, often remaining in tetrads, with the distal face densely areolate to partially lamellate, with 6--8 small areolae across the diameter .................................................................................................. 4. Fossombronia incurva

1.  Plants prostrate to rarely ascending, never with a subterranean rhizome-like axis; leaves oblique, never almost transverse, horizontal to patent, rarely erect, plane to undulate, rarely crispate, oblate, quadrate, or longer than wide, with apices entire or variously lobed; spores more than 35 /um, never remaining in tetrads, distal face sculpturing areolate or lamellate to cristate.

2.  Dioicous; leaves erect, crispate, oblate to subquadrate, margins shallowly lobed; caulocalyx stipitate, with the mouth erect to slightly recurved; spore distal face areolate, with 3--5 areolae across the diameter, some incompletely formed .............................................................................................. 6. Fossombronia marshii

2.  Monoicous; leaves horizontal to patent or erect, plane to undulate or crispate, longer than wide to quadrate or oblate, with or without marginal lobing; caulocalyx sessile or stipitate, with the mouth incurved, erect or recurved; spore distal face areolate or lamellate to partially cristate.

3.  Spores with distal face lamellate, with lamellae regularly or irregularly arranged, sometimes forming 1--3 central areolae, or dissected to form cristae, rarely becoming echinate.

4.  Leaves longer than broad to subquadrate, obtrapezoidal; stems forming descending subterranean apical tubers; protandrous, with antheridia widely separated from archegonia; lamellae densely spaced, with their free margins unevenly serrate, often dissected to form cristae or spines, forming 32--44 spinose projections around the distal face circumference,; elaters more than 280 /um long .................................................................... 5. Fossombronia longiseta

4.  Leaves oblate, or if longer than broad with a small marginal, dorsal auricle; stems never forming descending, subterranean apical tubers; not protandrous, with antheridia and archegonia intermixed; lamellae with their free margins never serrate, or dissected into cristae or spines, forming less than 33 truncate, acute or spinose projections around the distal face circumference; elaters less than 225 /um long

5.  Leaves lingulate to oblate, with small, basiscopic dorsal auricles, with leaf apices rounded to truncate, unlobed; spore distal face lamellae irregularly spaced, often cross-linked with fine thread-like ridges, forming 15--20, short truncate projections around the distal face circumference; spore proximal face densely verrucate to tuberculate, with well-defined triradiate ridge ................................................................................. 10. Fossombronia texana

5. Leaves oblate to subquadrate, never with basiscopic dorsal auricles, with leaf apices irregularly 3--4-lobed, with the lobes acute to rounded; spore distal face lamellae regularly spaced, never with cross-linking threads, forming 28--33 acute or 15--23 spinose projections around the distal face circumference; spore proximal face verrucate to cristate, without defined triradiate ridge.

6. Caulocalyx stipitate, with a few low, surface lamellae; spore distal face lamellae 4--8 /um high, forming 15--23 spinose projections around the circumference ........................................................ 8. Fossombronia pusilla

6. Caulocaylx sessile, with the surface lacking low lamellae; spore distal face lamellae 2--3 /um high, forming 28--33 acute projections around the circumference .......................................... 11. Fossombronia wondraczekii

3.  Spores with distal face areolate, with areolae completely or partially formed, and then appearing partially lamellate.

7.  Leaves never longer than wide, quadrate to oblate, undulate to crispate.

8.  Plants small, less than 1.5 mm wide; antheridia always associated with small perigonial scales; caulocalyx shortly stipitate, urnulate to narrowly campanulate, with the mouth constricted, incurved, with 3--4 angulate horn-like projections at its apex; spore distal face with 7--10 small areolae across the diameter, sometimes partially lamellate ............................................................................. 1. Fossombronia alaskana

8.  Plants medium, more than 2 mm wide; perigonial scales rarely present;  caulocalyx with a long basal stipe, pyriform to campanulate, with the mouth broad, recurved, irregularly dentate to lobed; spore distal face with 5--7 fully formed areolae across the diameter, never partially lamellate ............................................................................. 3. Fossombronia foveolata

7.  Leaves longer than wide to rarely quadrate, plane to slightly undulate, never crispate.

9.  Caulocalyx with a broad sinus on one side, with the mouth recurved, undulate, unlobed, with the margin entire; spore distal face with 4--6 fully formed areolae across the diameter, never partially lamellate; elaters few or absent 20--75 /um long, with a single spiral or annular thickening band .................................................................. 2. Fossombronia cristula

9.  Caulocalyx lacking a broad sinus, with the mouth recurved, lobed with the margin sparsely dentate; spore distal face with 3--5 irregularly formed areolae across the diameter, some areolae incompletely formed; elaters abundant, elongate, up to 160 /um long, with 2--3 or more spiral thickening bands.

10.  Stems never forming tubers; antheridia and archegonia intermixed; perigonial scales absent; elaters with 3--5 spiral thickening bands        .................................................................. 7. Fossombronia porphyrorhiza

10.  Stems sometimes forming apical and/or ventral tubers; protandrous, with antheridia and archegonia spatially separated; large, persistent perigonial scales present; elaters with 2--3 spiral thickening bands ...................................................................... 9. Fossombronia salina

1. Fossombronia alaskana Steere & Inoue, Bryologist 77: 66. 1974

Plants prostrate, 1.2--1.5 mm wide, in compact rosettes on silty, calcareous soils. Stems persistent, with apices becoming tuberous on older plants. Leaves imbricate, patent to erect, undulate, inserted dorsally to the stem midline, quadrate to slightly oblate, with the margins entire to shallowly lobed or angulate, sometimes tinged with purple. Sexual condition monoicous, protandrous (autoicous). Antheridia clustered at shoot apices, subtended by or intermixed with small, triangular scales. Caulocalyx 1(--2) per shoot, urnulate to campanulate, bearing a few wing-like, vertical lamellae, shortly stipitate; the mouth constricted prior to sporophyte maturation, with the lobed margin incurved, forming 3--4 angulate projections at its narrow opening, clasping the mature capsule prior to seta    elongation. Spores yellow-brown, 38--42(--46) /um; the distal face densely areolate, with 7--10 small areolae across the spore face, or partially lamellate, with the lamellae incompletely cross-linked, appearing furcate; the lamellae forming 28--35 short spinose projections around the circumference; equatorial wing absent; the proximal face verrucate to cristate, without a triradiate ridge. Elaters numerous, 173--290 x 7--12 /um, unbranched, with 2 spiral-thickening bands, occasionally with 3 bands medially; the bands moderately coiled.

On silt outflow of "frost boils" in Arctic or alpine tundra; circumarctic, low to high elevations; Greenland; Nfld. and Labrador (Labrador); Alaska; Eurasia (Russian Far East, Siberia, Yamal Peninsula)

Although somewhat similar to F. foveolata, F. alaskana is easily differentiated from this and all other species of Fossombronia by the unique appearance of its angulate, somewhat "horned," constricted caulocalyx mouth. In F. alaskana, the caulocalyx stipe is very short, in contrast to the long stipe usually developed in F. foveolata, and the spore areolation is lower and more variable, with smaller and more numerous lamellae and areolae, than typical of F. foveolata. As noted by W. C. Steere and H. Inoue (1974), in Alaska the species is restricted to the calcareous, fine silt of frost boils, and is fairly widespread in the Brooks Range Province. D. M. Krayesky et al. (2005) identified single specimens, from North Korea and Hokkaido, respectively, as F. alaskana, but further study indicates that neither of these specimens is F. alaskana. Both specimens have only immature sporophytes, but neither possesses the patent to erect leaves or the constricted, angulate caulocalyx that are diagnostic of F. alaskana. Vegetatively, the plants approach F. foveolata, but a definitive identification is not possible.

SELECTED REFERENCES  Krayesky, D. M., B. Crandall-Stotler & R. E. Stotler. 2005. A revision of the genus Fossombronia Raddi in East Asia and Oceania. J. Hattori Bot. Lab. 98: 1--45.   Steere, W. C. & H. Inoue. Fossombronia alaskana, a new hepatic from Arctic Alaska. Bryologist 77: 63--71.

2. Fossombronia cristula Austin, Proc. Acad. Nat. Sci. Philadelphia 21: 228. 1869  E

Fossombronia foveolata Lindberg var. cristula (Austin) R. M. Schuster, Hepat. Anthocerotae N. Amer. 5: 383. 1992

Plants prostrate, 0.7--2.5 mm wide, in small mats over moist, often sandy soil in disturbed habitats. Stems never tuberous. Leaves contiguous to slightly imbricate, horizontal, plane to slightly undulate, only slightly inserted on the dorsal side of the stem, oblong to lingulate, rarely quadrate, with the margins entire to shallowly lobed. Sexual condition monoicous. Antheridia intermixed with archegonia; perigonial scales absent. Caulocalyx up to 4 per shoot, broadly campanulate, sessile (nonstipitate), with a longitudinal opening or sinus on one side, with the surface smooth; the mouth broad, with the margin undulate, recurved. Spores light brown, 36--50 /um; the distal face areolate, with 4--6 areolae across the spore face, with the lamellae forming 13--16 short projections around the circumference; equatorial wing present, often incomplete; the proximal face finely cristate, without a triradiate ridge. Elaters few, sometimes absent, short and stout, 20--75 /um x 6--19 /um, often branched, with annular or 1-spiraled thickening bands; the bands loosely coiled.

Found on moist, denuded soils, often in disturbed habitats, such as paths, ditches and lake or stream banks; low to moderate elevation; Conn., Ill., Ind., Mass., Md., Mich., N.J., N.Y., N.C., Ohio, Tenn., W.Va.

Fossombronia cristula is considered endemic to the eastern United States. Schuster (1992) reduced F. cristula to varietal status under F. foveolata, while recognizing F. japonica as a synonym, therein extending the distribution of the taxon from eastern North America to Asia and Indonesia. A combination of morphological and molecular evidence confirms, however, that F. cristula is distinct at the species level from both F. japonica and F. foveolata (Krayesky et al. 2005; Scott & Crandall-Stotler 2002). Characters that unambiguously distinguish F. cristula from F. foveolata are 1) leaves that are oblong to lingulate rather than oblate, 2) antheridia and archegonia that develop simultaneously (intermixed) rather than being protandrous (spatially separated), caulocalyces that are sessile, rather than long, stipitate, and elaters that are very short, with single thickening bands.  

SELECTED REFERENCES  Krayesky, D. M., B. Crandall-Stotler & R. E. Stotler. 2005. A revision of the genus Fossombronia Raddi in East Asia and Oceania. J. Hattori Bot. Lab. 98: 1--45.   Schuster, R. M. 1992. The Hepaticae and Anthocerotae of North America, Vol. V. Field Museum, Chicago. 854 pp.   Scott, K. M. & B. J. Crandall-Stotler. 2002. RAPD polymorphism as an indicator of population structure, breeding system, and speciation in Fossombronia. Bryologist 105: 225--232.

3. Fossombronia foveolata Lindberg, Helsingf. Dagbl. 1873(353): 2. 1873

Plants prostrate to ascending, 2.1--3.2 mm wide, in small patches or tight mats over bare, usually acidic soil. Stems fleshy, persistent, never tuberous, ventrally with 2 rows of short 1-seriate filaments. Leaves imbricate, often crowded, horizontal to patent, undulate to crispate, shortly decurrent dorsally, oblate, with the margins irregularly dentate or lobed. Sexual condition monoicous, protandrous. Antheridia and archegonia spatially separated; perigonial scales absent, rarely present, then small, triangular to ligulate, nonpersistent. Caulocalyx 1--3 per shoot, pyriform to campanulate, with a long basal stipe, bearing a few scale-like lamellae on the surface; the mouth broad, with the margin irregularly dentate to lobed, recurved. Spores brown to dark brown, 38--54 /um; the distal face areolate, with 5--7 areolae across the spore face, with the lamellae forming 16--22 short truncate projections around the circumference; equatorial wing present, incomplete; the proximal face finely cristate, without a triradiate ridge. Elaters abundant, elongate, 90--165 /um x 6--15 /um, with 2 spiral-thickening bands, sometimes becoming 3 bands medially; the bands tightly to moderately, never loosely, coiled.

A widespread temperate species found on a variety of soil types, including bare spots in mowed grasslands, intermittently flooded shores of lakes and streams, soil pockets in sandstone glades, and organic muck of peaty bogs: low to moderate elevations; B.C., Nfld., N.S., Ont., Que.; Ark., Conn., Del., Ill., Ky., La., Maine, Md., Mass., Mich., Minn., Miss., Mo., N.H., N.J., N.Y., N.C., Ohio, Okla., Oreg., Pa., R.I., S.C., Tenn., Tex., Vt., Wash., W.Va., Wisc.; Europe; Africa (Azores, Madagascar, Morocco, S. Africa, Tanzania, Zaïre)

Although there is a detailed description and illustration of Fossombronia foveolata in S. O. Lindberg (1874: 382), this publication is not the correct author citation for the taxon, as mistakenly indicated in R. E. Stotler and Crandall-Stotler (2017: 614). The species was actually first named with a very brief, but valid, description in the Finnish newspaper "Helsingfors Daglad" in Dec. 1873, as indicated in the corrected citation above.

Collections labeled Fossombronia foveolata are among the most abundant specimens of Fossombronia in North American herbaria. This species is common in our flora, but is often misidentified, especially in southern and/or swampy eastern coastal habitats, because of similarities between its areolate spores and those of F. porphyrorhiza and F. salina. Although spore characters do not separate these species (G. A. M. Scott and D. C. Pike 1987) a suite of other characters do. Diagnostic characters of F. foveolata include leaves that are oblate, undulate to crispate, and lobed or dentate, antheridia and archegonia that are temporally and spatially separated, without perigonial scales, a caulocalyx that always has a medium to long, well-developed stipe, and elongate elaters that have two tightly coiled spiral-thickening bands, sometimes with 3 bands centrally. In contrast, leaves in both F. porphyrorhiza and F. salina are oblong-rectangular, planate to undulate, and entire, and caulocalyces are sessile to very shortly stipitate. Antheridia and archegonia are intermingled in F. porphyrorhiza, and spatially separated in F. salina, but with large persistent, perigonial scales subtending each antheridium. Elaters in both species have moderately to loosely coiled spiral bands, which number 3--5 in F. porphyrorhiza and 2--3 in F. salina.

SELECTED REFERENCES  Lindberg, S. O. 1874. Manipulus Muscorum Secundus. Not. Sällsk. Fauna Fl. Fenn. Förh. 13: 351--417.   Scott, G. A. M. & D. C. Pike. 1987. The Fossombronia foveolata complex. Lindbergia 13: 79--84.   Stotler, R. E. & B. Crandall-Stotler. 2017. A synopsis of the liverwort flora of North America North of Mexico. Ann. Mo. Bot. Gard. 102: 574--709.

4. Fossombronia incurva Lindberg, Helsingf. Dagbl. 1873(273): 2. 1873

Fossombronia fleischeri Osterwald, Veranst. Stadt Berlin Förd. Naturwiss. Unterr. Höh.  Lehranstalten 10: 24. 1910.

Plants erect, with leafy shoots 1--1.7 mm wide arising from a persistent subterranean rhizome, isolated or in small tufts on moist sandy soils. Stems fleshy, thick, becoming rhizomatous at the base, persistent. Leaves imbricate, erect, crispate, with the antical insertion almost transverse, extending to the stem midline, oblate to quadrate, with the margins 3--4(--5)-lobed, dentate. Sexual condition dioicous, with male plants smaller. Antheridia clustered near shoot apices, in dorsal axils of leaves; perigonial scales absent. Caulocalyx 1(--2) per shoot, cylindrical, sessile (nonstipitate), with the surface smooth; the mouth broad, with the margin undulate, entire to irregularly dentate, erect to slightly incurved. Capsule shape variable, obovoidal to ellipsoidal, or spheroidal. Spores reddish to purplish brown, free or united in tetrads 20--24(--28) /um; the distal face areolate, forming 6--8 small areolae across the spore face, sometimes with lamellae only partially anastomosing, with the lamellae forming 16--24 truncate projections around the circumference; equatorial wing present; the proximal face finely cristate, without a triradiate ridge. Elaters abundant, elongate, 90--165 x 6--15 /um, with 2 spiral-thickening bands, occasionally 3 bands medially; the bands tightly coiled.

A rare species found on moist sandy or gravelly soils, often along streams, lakes or in dune slacks; low to moderate elevation; Oreg.; nw Europe (Britain, Ireland, Poland, Finland, Sweden).

The inclusion of Fossombronia incurva in the North American flora is based on a series of collections made at Sutton Beach in Lane Co., Oregon, by David Wagner between June 2004 and June 2010 (D. H. Wagner 2014). Both male and female plants were found in small, scattered patches on a sandy stream terrace along Sutton Creek, growing with the also rare Haplomitrium hookeri in a community of mixed liverworts and hornworts. The taxon has not been found at the Sutton Beach site since 2011, but because of the restricted habitat and small size of this unique Fossombronia it is often overlooked (J. A. Paton 1999). Fossombronia incurva is distinguished from other species of Fossombronia by its small size, erect, leafy shoots that arise from a subterranean rhizome and its almost transversely inserted 3--5-lobed, dentate leaves. It is the only northern hemisphere species in which both spheroidal and more elongate, obovoidal to short ellipsoidal capsules can be developed in a single population. In fact, there is a mix of all three capsule shapes in specimens collected by S. O. Lindberg at the type locality of the species. Capsule wall thickenings, elater bands and spores are reddish brown. Although F. incurva resembles F. alaskana in spore wall architecture, its spores are much smaller and often remain in tetrads.

SELECTED REFERENCES  Paton, J. A. 1999. The Liverwort Flora of the British Isles. Colchester England. 626 pp.   Wagner, D. H. 2014. Guide to the Liverworts of Oregon. CD version, https://fernzenmosses.com/products-page/.

5. Fossombronia longiseta (Austin) Austin, Hepat. Bor.-Amer. Exsicc.: 118. 1873.

Androcryphia longiseta Austin, Proc. Acad. Nat. Sci. Philadelphia 21: 228. 1869.

Fossombronia hispidissima Stephani, Sp. Hepat. 1: 389. 1900.

Plants prostrate, 1.7--2.8 mm wide, forming dense mats over sandy loam in seasonally moist habitats. Stems semi-persistent, forming subterranean apical tubers during the dry season, ventrally with 2 rows of small triangular scales. Leaves imbricate, often crowded, horizontal to patent, undulate, with the antical insertion long, extending nearly to the stem midline, longer than broad to subquadrate, obtrapezoidal, with the apex truncate, entire to shallowly lobed. Sexual condition monoicous, protandrous. Antheridia and archegonia spatially separated; perigonial scales absent. Caulocalyx 1--4 per shoot, campanulate, sessile to shortly stipitate, with the surface smooth; the mouth broad, deeply lobed, recurved, with the margin sparingly dentate, sometimes with a vertical slit on one side. Spores yellowish brown, 45--65 /um; the distal face densely lamellate to cristate, often becoming echinate, with the lamellae 4--6 /um high, forming 32--44 spinose projections around the circumference; equatorial wing absent; the proximal face cristate to echinate, without a triradiate ridge. Elaters abundant, very long, 280--320 x 7--9 /um, with 2 spiral-thickening bands, rarely 3 bands medially; the bands loosely to moderately coiled.

A common species of exposed soil in western North America, widespread in California and southern Oregon; moderate to high elevation; B.C., Ariz., Calif., Oreg., Wash.; Mexico (Guadeloupe Isl., Sonora)

Historically, F. longiseta has been recognized as restricted to western North America (e.g., T. C. Frye and L. Clark 1937; M. A. Howe 1899), but R. M. Schuster (1992) reported that this species also occurs in Mississippi and Texas, based on his personal collections. Our study verifies, however, that all Schuster specimens cited from Texas are actually F. texana; unfortunately, the specimen cited by Schuster (1992: 394) from Mississippi cannot be located. As discussed further under the treatment of F. texana, although both F. longiseta and F. texana have lamellate spores, they differ in gametophytic characters, as well as in details of their spore wall and elater architectures. As indicated by Howe (1899) and illustrated by M. P. Steincamp and W. T. Doyle (1983: Fig. 1), the spores of F. longiseta display a wide range of architecture, even within a single capsule. In the west, the only species with which F. longiseta is likely to be confused is F. pusilla, which recent evidence confirms does occur in California (W. T. Doyle & R. E. Stotler 2006). Diagnostic characters of F. longiseta include the following: stem apices form descending subterranean tubers after spore release; leaves are longer than wide and dorsally inserted nearly to the stem midline, with apices truncate and entire; the caulocalyx is sessile to only shortly stipitate, and usually without elongate, vertical lamellae; spores vary from densely lamellate to cristate/echinate, with lamellae 4--6 /um high, with their free margins crenulate to serrate; elaters are very long, as first noted by C. F. Austin (1869), usually with the spiral bands very loosely coiled.

SELECTED REFERENCES  Austin, C. F. 1869. Characters of some new Hepaticae (Mostly North American), together with notes on a few imperfectly described species. Proc. Acad. Nat. Sci. Philadelphia 21: 218--234.   Doyle, W. T. and R. E. Stotler. 2006. Contributions toward a bryoflora of California III. Keys and annotated species catalogue for liverworts and hornworts. Madroño 53: 89-197.   Frye, T. C. and L. Clark. 1937. Hepaticae of North America. Univ. Washington Publ. in Biology 6 (1): 1--162.   Howe, M. A. 1899. Hepaticae and Anthocerotae of California. Mem. Torrey Bot. Club. 7: 1--208. pl. 88--122.   Schuster, R. M. 1992. The Hepaticae and Anthocerotae of North America, Vol. V. Chicago.  Steinkamp, M. P. and W. T. Doyle. 1983. Spore wall ultrastructure in the liverwort Fossombronia longiseta. Canad. J. Bot. 62: 1871--1879.

6. Fossombronia marshii J. R. Bray & Stotler, Phytologia 92: 230--231. 2010   E

Plants prostrate, 0.7--2.3 mm wide, forming small rosettes over loose sandy to sandy-loam soils in seasonally dry habitats. Stems dorsally flattened, forming subterranean apical tubers during the dry season, ventrally with 2 rows of 3-celled hairs. Leaves densely imbricate, erect, crispate, with the antical insertion long, extending to or crossing the stem midline, oblate to subquadrate, with the apex slightly rounded; the margin shallowly lobed, with the lobes rounded or acute. Sexual condition dioicous, dimorphic, with female plants almost twice the size of male plants. Antheridia large, yellowish orange, densely clustered, subtended by dorsal lobes of the leaves; perigonial scales absent. Caulocalyx 1--3 per shoot, narrowly campanulate, stipitate, with the surface bearing a few lanceolate scales, or smooth; the mouth broad, erect to slightly recurved, with the margin acutely lobed. Spores yellowish brown, 32--43 /um; the distal face areolate, 3--5 areolae across the diameter, with some incompletely formed, with the lamellae 3--5 /um high; 10--14 lamellar projections around the circumference; equatorial wing low, inconspicuous; the proximal face cristate, without a triradiate ridge. Elaters abundant, 70--123 x 11--19 /um, with 2--3(--4) spiral-thickening bands; the bands loosely coiled.

A localized endemic of the West Gulf Coastal plain; moderate elevations; Ark., La., Miss.

Fossombronia marshii is a recently discovered dioicous species of Fossombronia. Male plants, with their large, clustered orange antheridia, are diagnostic of the species, occurring in no other North American taxa. Without males, however, the species might be misidentified as F. foveolata, especially if there is a reliance on spore characters for identification. Like F. foveolata, the caulocalyx of F. marshii is distinctly stipitate, and spores are distally areolate, although with only 3--5 areolae across the diameter in contrast to the 5--7 areolae found in F. foveolata. In addition, F. marshii differs in elaters bearing 3--4 loosely coiled spiral-thickening bands, leaves erect and highly crispate, and plants forming apical tubers at the end of the growing season.

SELECTED REFERENCES  Stotler, R. E., B. Crandall-Stotler & J. R. Bray, Jr. 2010. Fossombronia marshii (Marchantiophyta), a new liverwort species from Arkansas. Phytologia 92: 230--232.

7. Fossombronia porphyrorhiza (Nees) Proskauer, Bryologist 58: 197. 1955

Jungermannia porphyrorhiza Nees, Fl. Bras. Enum. Pl. 1: 343. 1833; Fossombronia brasiliensis Stephani; Fossombronia pusilla subsp. cristatella R. M. Schuster ex Bonner

Plants prostrate, 2--3.6 mm wide, in small patches over moist soil or rocks, often in shaded habitats. Stems dorsally flattened, fragile, never tuberous, ventrally with 2 rows of 4--5-celled, 1-seriate filaments. Leaves distant to imbricate, horizontal to patent, plane to slightly undulate, with the antical insertion shortly decurrent, not extending to the stem midline, rectangular to spathulate, rarely quadrate, with the apex truncate to rounded, occasionally shallowly lobed; margins entire. Sexual condition monoicous. Antheridia scattered, intermixed with archegonia; perigonial scales absent. Caulocalyx 2--4 per shoot, campanulate, sessile to shortly stipitate, smooth; the mouth lobed, recurved, with the margin sparsely dentate. Spores brown to yellow brown, 38--55 /um; the distal face irregularly areolate, with 3--5(--6) areolae across the spore face, some incompletely formed, with the lamellae 2--4 /um high; 7--13 short lamellar projections around the circumference; equatorial wing absent ; the proximal face finely cristate, without a triradiate ridge. Elaters abundant, elongate, 90--140 x 8--12 /um, with (2--)3--5 spiral thickening bands; the bands loosely coiled.

A widespread, common species of the neotropics that extends into the coastal plain of the southeastern United States; low to moderate elevation; Ala., Fla., Ga., La., Miss., N.C., Tex., Mexico, West Indies, Central America, South America

The name Fossombronia brasiliensis Steph. has traditionally been applied to this species (e.g., T. C. Frye and L. Clark 1937; R. M. Schuster 1992) but since it is now considered a synonym of the earlier named F. porphyrorhiza, the accepted name for the species is F. porphyrorhiza (V. A. Freire 2002; S. R. Gradstein and D. C. da Costa 2003). On the basis of somewhat similar spore wall architectures, F. porphyrorhiza is frequently confused with F. foveolata and F. salina. As discussed under F. foveolata, F. porphyrorhiza differs from F. foveolata in having leaves that are longer than wide, antheridia and archegonia intermixed, sessile to very shortly stipitate caulocalyes, elaters with 3--5 loosely coiled spiral thickening bands, and fewer than 5 areolae across the distal spore face, with a tendency for some areolae to be incompletely formed. Fossombronia porphyrorhiza and F. salina have very similar spore and elater morphologies, as well as leaves that are longer than wide, but F. salina is protandrous and possesses well-developed perigonial bracts that persist as large dorsal scales after antheridial degeneration. In addition, some populations of F. salina produce numerous pendulous tubers along the ventral side of the stem, a character that is never expressed in F. porphyrorhiza. Unambiguous identification of F. porphyrorhiza versus F. foveolata or F. salina requires evaluation of this entire suite of characters. R. M. Schuster (1992) mistakenly described some populations of F porphyrorhiza from North America has having lamellate, rather than areolate spores, but personal study of all specimens cited with this character verifies that they are actually F. texana, including the type of F. brasiliensis var. lamellifera R. M. Schuster, nom. inval. (see R. M. Schuster 1992: Fig. 835 as well as discussion under F. texana).

SELECTED REFERENCES  Freire, V. A. 2002. A Revision of the Genus Fossombronia in Latin America. Doctoral Dissertation, Southern Illinois University, Carbondale, IL. 275 pp.   Frye, T. C. & L. Clark. 1937. Hepaticae of North America. Univ. Washington Publ. in Biology 6 (1): 1--162.   Gradstein, S. R. and D. P. da Costa. 2003. The Hepaticae and Anthocerotae of Brazil. Mem. N.Y. Bot. Gard. 87: 1--318. Schuster, R. M. 1992. The Hepaticae and Anthocerotae of North America, Vol. V. Chicago.

8. Fossombronia pusilla (Linnaeus) Nees, Naturgesch. Eur. Leberm. 3: 319. 1938

Jungermannia pusilla Linnaeus, Sp. Pl. 2: 1136. 1753; Fossombronia loitlesbergeri Schiffner; F. pusilla var. maritima Paton; F. maritima (Paton) Paton

Plants prostrate to ascending, 2--3.5 mm wide, forming mats over moist soil, often shaded by near-by vegetation. Stems fragile, decaying with age, or fleshy, persistent, with apices becoming tuberous but never forming elongate subterranean tubers, ventrally with 2 rows of small triangular, 3-lobed scales. Leaves contiguous to imbricate, horizontal to subpatent, undulate, with the antical insertion shortly decurrent, not extending to the stem midline, oblate to subquadrate, with the apex truncate, lobed with the lobes acute to rounded. Sexual condition monoicous. Antheridia scattered, intermixed with the archegonia; perigonial scales absent. Caulocalyx 1--2 per shoot, campanulate, stipitate, with the surface bearing a few low vertical lamellae; the mouth broad, deeply lobed, with the lobes acute or rounded, erect to recurved, with the margins entire. Spores yellowish brown to dark brown, 38--58 /um; the distal face lamellate, with the lamellae sometimes anastomosing to form a central areola; lamellae 4--8 /um high, forming 15--23 spinose projections around the circumference; equatorial wing incomplete or absent; the proximal face verrucate to cristate, without a triradiate ridge. Elaters abundant, 160--225 x 7--9 /um, with 2 spiral-thickening bands, rarely 3 bands medially; the bands moderately to tightly coiled.

Cosmopolitan species, found on open soil in a variety of habitats, in North America restricted to the west coast; moderate to high elevations; Calif., Oreg.; w South America; Europe; Asia; Africa; New Zealand; Australia

Reports of Fossombronia pusilla from eastern North America are based on misidentifications, but its occurrence in the Pacific Northwest has been verified (J. R. Bray 2001; B. Crandall-Stotler et al. 2019; W. T. Doyle and R. E. Stotler 2006). The California and Oregon populations of F. pusilla are perennial with fleshy, persistent tuberous stems and have spores with up to 23 lamellar projections, a morphotype sometimes recognized as F. pusilla subsp. maritima (J. E. Paton 1973) or F. maritima (J. E. Paton 1994). Fossombronia pusilla is distinguished from both F. longiseta and F. texana, which have leaves that are longer than wide, by its marginally lobed, oblate to subquadrate leaves. The distal spore wall lamellae in F. pusilla are fewer in number than occurs in F. longiseta, have entire, rather than serrated, free margins, are never dissected into cristae or spines, and frequently form central areolae. The lamellae are much higher than those in F. texana, and lack the thread-like interconnecting cross-ridges commonly seen in this species. Fossombronia pusilla resembles F. wondraczekii in leaf shape and insertion, but is less branched, has a fleshy, tuberous stem and is of larger size. Also, the caulocalyx of F. wondraczekii is sessile and smooth, rather than stipitate as in F. pusilla, and its spores have more numerous, more closely spaced, shorter, thinner lamellae than those in F. pusilla.  

SELECTED REFERENCES  Crandall-Stotler, B. J., J. C. Benavides, R. E. Stotler and L. L. Forrest. 2019. A new species of Fossombronia (Marchantiophyta, Fossombroniineae, Fossombroniaceae) from high elevation mires in Latin America. Bry. Div. Evo. 41: 2--16.   Doyle, W. T. and R. E. Stotler. 2006. Contributions toward a bryoflora of California III. Keys and annotated species catalogue for liverworts and hornworts. Madroño 53: 89--197.   Evans, A. W. 1923. Notes on the Hepaticae of California. Proc. Cal. Acad. Sci. 13: 111--130.   Paton, J. E. 1973. Taxonomic studies in the genus Fossombronia Raddi. J. Bryol. 7: 243--252.   Paton, J. E. 1994. Fossombronia pusilla (L.) Nees var. maritima Paton elevated to the rank of species. J. Bryol. 18: 366--368.   Schuster, R. M. 1992. The Hepaticae and Anthocerotae of North America, Vol. V. Chicago.

9.  Fossombronia salina Lindberg ex A. Evans, Rhodora 3: 9. 1901   F

Fossombronia lamellata sensu A. Evans, Bryologist 20: 19. 1917, not Stephani, Hedwigia 33: 9. 1894

Plants prostrate, 1.6--3.5 mm wide, forming mats over soil in ditches or swampy meadows, often in brackish habitats; occasional on rotting logs. Stems dorsally flattened, nonpersistent, in some populations forming tubers, either at stem apices or from the apices of short branches arising ventrally all along, narrow somewhat etiolated plants. Leaves distant to imbricate, horizontal to subpatent, plane to slightly undulate, with the antical insertion shortly decurrent, not extending to the stem midline, quadrate to oblong, with the apex truncate, occasionally shallowly lobed, with the lobes rounded, rarely acute to apiculate; margins entire. Sexual condition monoicous, protandrous. Antheridia and archegonia spatially separated; perigonial scales intermixed with antheridia, rectangular to lanceolate, apically 2-lobed, basally concave, with the margins entire to crenulate, persistent and enlarging after antheridial degeneration. Caulocalyx 1--3 per shoot, broadly campanulate, sessile to shortly stipitate, smooth; the mouth deeply lobed with the lobes rounded or acute, erect to recurved, with the margin entire. Spores brown to yellow brown, 40--50 /um; the distal face areolate, with 3--5(--6) areolae across the spore face, some incompletely formed, with the lamellae 2--4 /um high; 12--15 short lamellar projections around the circumference; equatorial wing absent; the proximal face finely

cristate, without a triradiate ridge. Elaters abundant, elongate, 110--160 x 8--15 /um, with 2--3 spiral thickening bands; the bands moderately to loosely coiled.

In North America restricted to wet, often swampy habitats in the eastern coastal plain, from Maine to central Florida; low elevations; Conn., Fla., Maine, N.J., R.I.; West Indies (Cuba)

Fossombronia salina is generally considered conspecific with either F. porphyrorhiza A. W. Evans 1923; R. M. Schuster 1992) or F. foveolata (G. A. M. Scott and D. C. Pike 1987), based on similarities in spore wall architecture. Known only from wet, often brackish habitats in low elevation sites of the Atlantic coastal plain, F. salina is morphologically very similar to F. porphyrorhiza, but differs as follows: F. salina is decidedly protandrous, with clusters of antheridia and archegonia spatially separated, and has large, foliose, persistent perigonial scales whereas F. porphyrorhiza forms intermixed antheridia and archegonia and lacks perigonial scales; elaters in F. salina have 2--3 thickening bands, while elaters in F. porphyrorhiza usually have 4--5 thickening bands; in F. salina the caulocalyx mouth is deeply divided into erect to broadly reflexed, rounded lobes, with entire margins, as compared to the less reflexed, shallowly lobed, dentate caulocalyx mouth common in F. porphyrorhiza; some populations of F. salina form apical and /or short, ventral, tuberous branches that are never formed in F. porphyrorhiza. Apical tubers have been seen in collections from coastal Maine, central Florida, and Isles of Pines, Cuba, while tuberous ventral branches have been found only in collections from Florida. This latter form was mistakenly treated as F. lamellata Steph. by A. W. Evans (1917) and R. M. Schuster (1992: Fig. 846).

SELECTED REFERENCES  Evans, A. W. 1917. Notes on North American Hepaticae. VII. Bryologist 20: 17--28.   Evans, A. W. 1923. Notes on New England Hepaticae. XVII. Rhodora 25: 74--83, 89--98.   Schuster, R. M. 1992. The Hepaticae and Anthocerotae of North America, Vol. V. Chicago.   Scott, G. A. M. & D. C. Pike. 1987. The Fossombronia foveolata complex. Lindbergia 13: 79--84.

10. Fossombronia texana Lindberg, Acta Soc. Sci. Fennicae 10: 533. 1875

 Fossombronia mexicana Stephani

Plants prostrate, 1.6--3 mm wide, forming loose to dense mats over calcareous substrates, including limestone, marl or travertine, often in shaded habitats along rivers. Stems dorsally flattened, fleshy, persistent, with apices becoming tuberous, ventrally with 2 rows of 2--3-celled, 1-seriate filaments. Leaves imbricate, patent to horizontal, plane to slightly undulate, antically inserted nearly to the stem midline, often with a small, lobule or auricle near the base of the antical margin, lingulate to oblate, with the apex rounded to truncate, sometimes emarginate or weakly lobed; margins entire to sparsely dentate. Sexual condition monoicous. Antheridia scattered, intermixed with archegonia; perigonial scales absent. Caulocalyx 1--2(--3) per shoot, narrowly campanulate, stipitate, smooth; the mouth broadly lobed, erect to recurved, with the lobes short and broad and the margin entire or sparsely dentate. Spores brown to reddish brown, 42--57 /um; the distal face irregularly lamellate, with the lamellae 2--3.5 /um high and less than 2 /um in thickness, often with a fine network of thread-like cross-ridges between lamellae; 15--20 short truncate to acute lamellar projections around the circumference; equatorial wing lacking or partially formed between lamellae; the proximal face densely verrucate to tuberculate, with verrucae small, rounded; triradiate ridge, usually present. Elaters abundant, elongate, 90--140 x 8--12 /um, with 2 spiral thickening bands, rarely becoming 3 bands medially; the bands loosely coiled.

Restricted to calcareous substrates, often forming dense carpets on loose marl in shady areas, along riverbanks and on drip walls in the Interior Highlands and Texas Hill Country; low to moderate elevations; Ark., Mo., Okla., Tex.; Mexico; West Indies (Cuba); Atlandtic Islands (Bermuda).  

Since its naming by S. O. Lindberg in 1875, F. texana has been an enigmatic, poorly understood taxon. T. C. Frye and L. Clark (1937) provided a brief description of the taxon, without illustration, and unfortunately, in R. M. Schuster (1992) specimens of F. texana are confused with F. porphyrorhiza and F. longiseta; e.g., all of Fig. 842 and 845 are F. texana, not F. longiseta and F. brasiliensis, as repectively labeled. Characters of F. texana that distinguish it from these other species include leaves that are longer than broad, often patent and slightly undulate, frequently with a well-developed auricle near its dorsal insertion; stems that are broad, darkly pigment, and apically persistent, but not forming tubers; a long stipitate caulocalyx; and spores ornamented with short thin lamellae, interconnected with fine, thread-like cross-bridges on the distal face, and short verrucae or tubercles on the proximal surface, with a distinct triradiate ridge.

SELECTED REFERENCES  Frye, T. C. & L. Clark. 1937. Hepaticae of North America. Univ. Washington Publ. in Biology 6 (1): 1--162.   Schuster, R. M. 1992. The Hepaticae and Anthocerotae of North America, Vol. V. Chicago.

11. Fossombronia wondraczekii (Corda) Dumortier ex Lindberg, Helsinf. Dagbl. 1873(273): 2. 1873

Jungermannia wondraczekii Corda in Sturm, Deutschl. Fl. Abt. II, Cryptog. 19--20: 30. 1830;  Fossombronia cristata Lindberg; F. macounii Austin

Plants prostrate, 1.5--2.4 mm wide, growing among other bryophytes or forming small rosettes over moist soil, often shaded by near-by vegetation. Stems dorsally flattened, decaying with age, rarely persistent. Leaves contiguous to imbricate, subpatent to erect, undulate to crispate, with the antical insertion shortly decurrent, not extending to the stem midline, oblate to subquadrate, with the apex truncate, irregularly lobed with the lobes acute to rounded. Sexual condition monoicous. Antheridia scattered, intermixed with the archegonia; perigonial scales absent. Caulocalyx 1--4, crowded together at the shoot apex, narrowly campanulate, sessile, with the surface smooth; the mouth lobed, with the lobes acute or rounded, erect, with the margins entire. Spores light to medium brown, 38--48/um; the distal face lamellate, with the lamellae parallel in lateral view, occasionally anastomosing distally to form 1 or 2 central areolae; lamellae low and thin, 2--3 /um high, less than 2 /um wide, blunt to slightly tapered, forming 28--33 short, truncate to acute projections around the circumference; equatorial wing absent; the proximal face verrucate to cristate, without a triradiate ridge. Elaters abundant, 57--95 /um long, with 2 spiral-thickening bands, rarely 3 bands medially; the bands moderately coiled.

Widely scattered, in North America restricted to moist soil habitats of the northeast, often in disturbed habitats, intermixed with other bryophytes; low to moderate elevations; Greenland; N.B., Ont., Que., Sask.; Conn., Ind., Mass., Md., N.C., N.H., N.Y., Ohio, Pa., Tenn., Vt., W.Va.; Europe; Northern Africa; Australia; Atlantic Islands (Iceland); Pacific Islands (New Zealand).

In North America, Fossombronia wondraczekii is fairly widespread from eastern Greenland south to the Appalachians, and westward into Ohio and Indiana. The inclusion of northwestern Saskatchewan in its distribution is based on the type and only collection of F. macounii Austin, which is herein placed in synonymy of F. wondraczekii. We have verified that specimens identified as F. wondraczekii from Texas (McAllister et al. 1932), as well as McGregor's specimens from Arkansas (Wittlake 1954) and Kansas, are F. texana, and all reports of this species from California and Oregon are based on misidentifications of F. longiseta. In contrast to these species, F. wondraczekii has erect, marginally lobed, oblate leaves like F. pusilla, from which it differs in its smaller size, highly branched, rosette-forming habit, and nonstipitate, narrowly companulate caulocalyx with a lobed, erect to incurved mouth. In addition to its smaller size, F. wondraczekii has a distinctive spore wall architecture in which the distal face lamellae are thin, less than 3 /um tall, acute to truncate, and aligned parallel to each other, forming 28--33 low, acute to truncate projections around the equatorial rim in contrast to 4--8 /um high, tapered lamellae and spinose rim projections of both F. pusilla and F. longiseta. In F. pusilla there are fewer than 20 lamellae across the face, and in F. longiseta the 32--44 lamellae, although densely spaced, are often broken up into short cristae and/or spines. Like F. wondraczekii, F. texana has spores with low, thin distal face lamellae, but these are fewer in number and more irregularly arranged than those of F. wondraczekii, and are interconnected with a fine network of thread-like thickenings between them. Also, even if these two species might be confused on the basis of spore morphology, they occur in very different habitats and differ greatly in size, leaf shape, insertion and stance, and caulocalyx morphology.

SELECTED REFERENCES  Macvicar, S. M. 1926. The Student's Handbook of British Hepatics, 2nd ed., Eastbourne, Sumfield. 464 pp.   McAllister, F., P. Y. Hoglund and E. Whitehouse. 1932. Catalogue of Texas Hepaticae. Transactions of the Texas Academy of Science 15: 39--59.   Wittlake, E. B. 1954. The Hepaticae of Arkansas. I. Bryologist 57: 7--18.