EMBRYOPSIDA Pirani & Prado (crown group)
Gametophyte dominant, independent, multicellular, thalloid, with single-celled apical meristem, showing gravitropism; flavonoids + [absorbtion of UV radiation]; protoplasm dessication tolerant [plant poikilohydric]; cuticle +; cell walls with (1->4)-ß-D-glucans [xyloglucans], lignin +; rhizoids unicellular; several chloroplasts per cell; glycolate metabolism in leaf peroxisomes [glyoxysomes]; centrioles in vegetative cells 0, metaphase spindle anastral, predictive preprophase band of microtubules, phragmoplast + [cell wall deposition spreading from around the spindle fibres], plasmodesmata +; antheridia and archegonia jacketed, stalked; spermatogenous cells monoplastidic, centrioles develop de novo, associated with basal bodies of flagellae, multilayered structure +, proximal end of basal bodies lacking symmetry, stellate pattern associated with doublet tubules of transition zone; spermatozoids with a left-handed coil; male gametes with 2 lateral flagellae; oogamy; diploid embryo initially surrounded by haploid gametophytic tissue, plane of first division horizontal [with respect to long axis of archegonium/embryo sac], suspensor/foot +, cell walls with nacreous thickenings; sporophyte multicellular, sporangium +, single, with polar transport of auxin, dehiscence longitudinal; meiosis sporic, monoplastidic, microtubule organizing centre associated with plastid, cytokinesis simultaneous, preceding nuclear division, sporocytes 4-lobed, with a quadripolar microtubule system; spores in tetrads, sporopollenin in the spore wall, wall with several trilamellar layers [white-line centred layers, i.e. walls multilamellate]; spores trilete; close association between the trnLUAA and trnFGAA genes on the chloroplast genome.
Note that many of the bolded characters in the characterization above are apomorphies in the streptophyte clade along the lineage leading to the embryophytes rather than being apomorphies of the crown embryophytes.
Abscisic acid, ?D-methionine +; sporangium with seta, seta developing from basal meristem [between epibasal and hypobasal cells], sporangial columella + [developing from endothecial cells]; stomata +, anomocytic, cell lineage that produces them with symmetric divisions [perigenous]; underlying similarities in the development of conducting tissue and in rhizoids/root hairs; polar transport of auxins and class 1 KNOX genes expressed in the sporangium alone; MIKC, MI*K*C* and class 1 and 2 KNOX genes, post-transcriptional editing of chloroplast genes; gain of three group II mitochondrial introns.
[Hornworts + Polysporangiophyta]: archegonia embedded/sunken in the gametophyte; sporophyte long-lived, chlorophyllous, nutritionally largely independent of the gametophyte; sporophyte-gametophyte junction interdigitate, sporophyte cells showing rhizoid-like behaviour.
Sporophyte well developed, branched, free living, sporangia several; spore walls not multilamellate [?here]; apical meristem +.
EXTANT TRACHEOPHYTA / VASCULAR PLANTS
Photosynthetic red light response; water content of protoplasm relatively stable [plant homoiohydric]; control of leaf hydration passive; (condensed or nonhydrolyzable tannins/proanthocyanidins +); vascular tissue +, sieve cells + [nucleus degenerating], tracheids +, in both protoxylem and metaxylem; endodermis +; root xylem exarch [development centripetal]; stem with an apical cell; branching dichotomous; leaves spirally arranged, blades with mean venation density 1.8 mm/mm2 [to 5 mm/mm2]; sporangia adaxial on the sporophyll, sporangia derived from periclinal divisions of several epidermal cells, wall multilayered [eusporangium]; columella 0; tapetum glandular; stellate pattern split between doublet and triplet regions of transition zone; placenta with single layer of transfer cells in both sporophytic and gametophytic generations, embryonic axis not straight [root lateral with respect to the longitudinal axis; plant homorhizic].[MONILOPHYTA + LIGNOPHYTA]
Branching ± monopodial; lateral roots +, endogenous, root apex multicellular, root cap +; tracheids with scalariform-bordered pits; leaves with apical/marginal growth, venation development basipetal, growth determinate; sporangia borne in pairs and grouped in terminal trusses, dehiscence longitudinal, a single slit; cells polyplastidic, microtubule organizing centres not associated with plastids, diffuse, perinuclear; male gametes multiflagellate, basal bodies staggered, blepharoplasts paired; chloroplast long single copy ca 30kb inversion [from psbM to ycf2].
Plant woody; lateral root origin from the pericycle; branching lateral, meristems axillary; cork cambium + [producing cork abaxially], vascular cambium bifacial [producing phloem abaxially and xylem adaxially].
EXTANT SEED PLANTS / SPERMATOPHYTA
Plant evergreen; nicotinic acid metabolised to trigonelline, (cyanogenesis via tyrosine pathway); primary cell walls rich in xyloglucans and/or glucomannans, 25-30% pectin [Type I walls]; lignins derived from (some) sinapyl and particularly coniferyl alcohols [hence with p-hydroxyphenyl and guaiacyl lignin units, so no Maüle reaction]; root with xylem and phloem originating on alternate radii, vascular tissue not medullated, cork cambium deep seated; arbuscular mycorrhizae +; shoot apical meristem interface specific plasmodesmatal network; stem with vascular cylinder around central pith [eustele], phloem abaxial [ectophloic], endodermis 0, xylem endarch [development centrifugal]; wood homoxylous, tracheids and rays alone, tracheid/tracheid pits circular, bordered; mature sieve tube/cell lacking functioning nucleus, sieve tube plastids with starch grains; phloem fibres +; stem cork cambium superficial; branches exogenous; leaves with single trace from vascular sympodium [nodes 1:1]; stomatal pore with active opening in response to leaf hydration, control by abscisic acid, metabolic regulation of water use efficiency, etc.; leaves with petiole and lamina, development basipetal, blade simple; axillary buds +, (not associated with all leaves); prophylls two, lateral; plant heterosporous, sporangia borne on sporophylls; microsporophylls aggregated in indeterminate cones/strobili; true pollen +, grains mono[ana]sulcate, exine and intine homogeneous; ovules unitegmic, parietal tissue 2+ cells across, megaspore tetrad linear, functional megaspore single, chalazal, lacking sporopollenin, megasporangium indehiscent; pollen grains landing on ovule; male gametophyte development first endo- then exosporic, tube developing from distal end of grain, gametes two, developing after pollination, with cell walls; female gametophyte endosporic, initially syncytial, walls then surrounding individual nuclei; seeds "large" [ca 8 mm3], but not much bigger than ovule, with morphological dormancy; embryo cellular ab initio, endoscopic, plane of first cleavage of zygote transverse, suspensor +, short-minute, embryonic axis straight [shoot and root at opposite ends; plant allorhizic], white, cotyledons 2; plastid transmission maternal; ycf2 gene in inverted repeat, whole nuclear genome duplication [zeta duplication], two copies of LEAFY gene, PHY gene duplications [three - [BP [A/N + C/O]] - copies], nrDNA with 5.8S and 5S rDNA in separate clusters; mitochondrial nad1 intron 2 and coxIIi3 intron and trans-spliced introns present.
Lignans, O-methyl flavonols, dihydroflavonols, triterpenoid oleanane, apigenin and/or luteolin scattered, [cyanogenesis in ANITA grade?], S [syringyl] lignin units common [positive Maüle reaction - syringyl:guaiacyl ratio more than 2-2.5:1], and hemicelluloses as xyloglucans; root apical meristem intermediate-open; root vascular tissue oligarch [di- to pentarch], lateral roots arise opposite or immediately to the side of [when diarch] xylem poles; origin of epidermis with no clear pattern [probably from inner layer of root cap], trichoblasts [differentiated root hair-forming cells] 0, exodermis +; shoot apex with tunica-corpus construction, tunica 2-layered; reaction wood ?, associated gelatinous fibres [g-fibres] with innermost layer of secondary cell wall rich in cellulose and poor in lignin; starch grains simple; primary cell wall mostly with pectic polysaccharides, poor in mannans; tracheid:tracheid [end wall] plates with scalariform pitting, wood parenchyma +; sieve tubes enucleate, sieve plate with pores (0.1-)0.5-10< µm across, cytoplasm with P-proteins, cytoplasm not occluding pores of sieve plate, companion cell and sieve tube from same mother cell; sugar transport in phloem passive; nodes 1:?; stomata brachyparacytic [ends of subsidiary cells level with ends of pore], outer stomatal ledges producing vestibule, reduction in stomatal conductance to increasing CO2 concentration; lamina formed from the primordial leaf apex, margins toothed, development of venation acropetal, overall growth ± diffuse, venation hierarchical-reticulate, secondary veins pinnate, veins (1.7-)4.1(-5.7) mm/mm2, endings free; most/all leaves with axillary buds; flowers perfect, pedicellate, ± haplomorphic, parts spiral [esp. the A], free, numbers unstable, development in general centripetal; P +, members each with a single trace, outer members not sharply differentiated from the others, not enclosing the floral bud; A many, filament not sharply distinguished from anther, stout, broad, with a single trace, anther introrse, tetrasporangiate, sporangia in two groups of two [dithecal], ± embedded in the filament, with at least outer secondary parietal cells dividing, each theca dehiscing longitudinally, endothecium +, endothecial cells elongated at right angles to long axis of anther; (tapetum glandular), cells binucleate; microspore mother cells in a block, microsporogenesis successive, walls developing by centripetal furrowing; pollen subspherical, tectum continuous or microperforate, ektexine columellate, endexine thin, compact, lamellate only in the apertural regions; nectary 0; carpels present, superior, free, several, ascidiate, with postgenital occlusion by secretion, stylulus short, hollow, cavity not lined by distinct epidermal layer, stigma ± decurrent, carinal, dry [not secretory]; ovules few [?1]/carpel, marginal, anatropous, bitegmic, micropyle endostomal, outer integument 2-3 cells across, often largely subdermal in origin, inner integument 2-3 cells across, often dermal in origin, parietal tissue 1-3 cells across [crassinucellate], nucellar cap?; megasporocyte single, hypodermal, functional megaspore lacking cuticle; female gametophyte four-celled [one module, nucleus of egg cell sister to one of the polar nuclei]; supra-stylar extra-gynoecial compitum +; ovule not increasing in size between pollination and fertilization; pollen grains landing on stigma, bicellular at dispersal, mature male gametophyte tricellular, germinating in less than 3 hours, pollination siphonogamous, tube elongated, growing between cells, growth rate (20-)80-20,000 µm/hour, apex of pectins, wall with callose, lumen with callose plugs, penetration of ovules via micropyle [porogamous], whole process takes ca 18 hours, distance to first ovule 1.1-2.1 mm; male gametes lacking cell walls, flagellae 0, double fertilization +, ovules aborting unless fertilized; P deciduous in fruit; seed exotestal, becoming much larger than ovule at time of fertilization; endosperm diploid, cellular, heteropolar [micropylar and chalazal domains develop differently, first division oblique, micropylar end initially with a single large cell, divisions uniseriate, chalazal cell smaller, divisions in several planes], copious, oily and/or proteinaceous; embryogenesis cellular; dark reversal Pfr -> Pr; Arabidopsis-type telomeres [(TTTAGGG)n]; 2C genome size 1-8.2 pg [1 pg = 109 base pairs], whole nuclear genome duplication [epsilon duplication]; protoplasm dessication tolerant [plant poikilohydric]; ndhB gene 21 codons enlarged at the 5' end, single copy of LEAFY and RPB2 gene, knox genes extensively duplicated [A1-A4], AP1/FUL gene, paleo AP3 and PI genes [paralogous B-class genes] +, with "DEAER" motif, SEP3/LOFSEP and three copies of the PHY gene, [PHYB [PHYA + PHYC]].
[NYMPHAEALES [AUSTROBAILEYALES [[CHLORANTHALES + MAGNOLIIDS] [MONOCOTS [CERATOPHYLLALES + EUDICOTS]]]]]: wood fibres +; axial parenchyma diffuse or diffuse-in-aggregates; pollen monosulcate [anasulcate], tectum reticulate-perforate [here?]; ?genome duplication; "DEAER" motif in AP3 and PI genes lost, gaps in these genes.
[AUSTROBAILEYALES [[CHLORANTHALES + MAGNOLIIDS] [MONOCOTS [CERATOPHYLLALES + EUDICOTS]]]]: vessel elements with scalariform perforation plates in primary xylem; essential oils in specialized cells [lamina and P ± pellucid-punctate]; tension wood +; tectum reticulate; anther wall with outer secondary parietal cell layer dividing; carpels plicate; nucellar cap + [character lost where in eudicots?]; 12BP [4 amino acids] deletion in P1 gene.
[[CHLORANTHALES + MAGNOLIIDS] [MONOCOTS [CERATOPHYLLALES + EUDICOTS]]] / MESANGIOSPERMAE: benzylisoquinoline alkaloids +; sesquiterpene synthase subfamily a [TPS-a] [?level], polyacetate derived anthraquinones + [?level]; outer epidermal walls of root elongation zone with cellulose fibrils oriented transverse to root axis; P more or less whorled, 3-merous [possible position]; pollen tube growth intra-gynoecial; embryo sac bipolar, 8 nucleate, antipodal cells persisting; endosperm triploid.
[MONOCOTS [CERATOPHYLLALES + EUDICOTS]]: (extra-floral nectaries +); (veins in lamina often 7-17 mm/mm2 or more [mean for eudicots 8.0]); (stamens opposite [two whorls of] P); (pollen tube growth fast).
[CERATOPHYLLALES + EUDICOTS]: ethereal oils 0.
EUDICOTS: (Myricetin, delphinidin +), asarone 0 [unknown in some groups, + in some asterids]; root epidermis derived from root cap [?Buxaceae, etc.]; (vessels with simple perforation plates in primary xylem); nodes 3:3; stomata anomocytic; flowers (dimerous), cyclic; K/outer P members with three traces, ("C" +, with a single trace); A few, (polyandry widespread, initial primordia 5, 10, or ring, ± centrifugal), filaments fairly slender, anthers basifixed; microsporogenesis simultaneous, pollen tricolpate, apertures in pairs at six points of the young tetrad [Fischer's rule], cleavage centripetal, wall with endexine; G with complete postgenital fusion, stylulus/style solid [?here]; seed coat?
[PROTEALES [TROCHODENDRALES [BUXALES + CORE EUDICOTS]]]: (axial/receptacular nectary +).
[TROCHODENDRALES [BUXALES + CORE EUDICOTS]]: benzylisoquinoline alkaloids 0; euAP3 + TM6 genes [duplication of paleoAP3 gene: B class], mitochondrial rps2 gene lost.
[BUXALES + CORE EUDICOTS]: ?
CORE EUDICOTS / GUNNERIDAE: (ellagic and gallic acids +); leaf margins serrate; compitum + [one place]; micropyle?; whole nuclear genome duplication [palaeohexaploidy, gamma triplication], PI-dB motif +, small deletion in the 18S ribosomal DNA common.
[ROSIDS ET AL. + ASTERIDS ET AL.] / PENTAPETALAE: root apical meristem closed; (cyanogenesis also via [iso]leucine, valine and phenylalanine pathways); flowers rather stereotyped: 5-merous, parts whorled; P = calyx + corolla, the calyx enclosing the flower in bud, sepals with three or more traces, petals with a single trace; stamens = 2x K/C, in two whorls, internal/adaxial to the corolla whorl, alternating, (numerous, but then usually fasciculate and/or centrifugal); pollen tricolporate; G , G  also common, when [G 2], carpels superposed, compitum +, placentation axile, style +, stigma not decurrent; endosperm nuclear; fruit dry, dehiscent, loculicidal [when a capsule]; RNase-based gametophytic incompatibility system present; floral nectaries with CRABSCLAW expression.
[SANTALALES [BERBERIDOPSIDALES [CARYOPHYLLALES + ASTERIDS]]] / ASTERIDS ET AL. / SUPERASTERIDS : ?
[BERBERIDOPSIDALES [CARYOPHYLLALES + ASTERIDS]]: ?
[CARYOPHYLLALES + ASTERIDS]: seed exotestal; embryo long.
ASTERIDS / Sympetalae redux? / ASTERIDAE / ASTERANAE Takhtajan: nicotinic acid metabolised to its arabinosides; (iridoids +); tension wood decidedly uncommon; C enclosing A and G in bud, (connate, if evident only early in development and then petals often appearing to be free); anthers dorsifixed?; (nectary gynoecial); style +, long; ovules unitegmic, integument thick, endothelium +, nucellar epidermis does not persist; exotestal cells lignified, esp. on anticlinal and/or inner periclinal walls; endosperm cellular.
[ERICALES [ASTERID I + ASTERID II]]: (ovules lacking parietal tissue) [tenuinucellate].
[ASTERID I + ASTERID II] / CORE ASTERIDS: ellagic acid 0, non-hydrolysable tannins not common; sugar transport in phloem active; inflorescence basically cymose; A = and opposite sepals or P, (numerous, usu. associated with increased numbers of C or G); style short[?]; duplication of the PI gene.
ASTERID II / CAMPANULIDAE: myricetin 0; vessel elements with scalariform perforation plates; endosperm copious, embryo short/very short.
[ASTERALES [ESCALLONIALES [BRUNIALES [APIALES [PARACRYPHIALES + DIPSACALES]]]]] / APIIDAE: iridoids +; C forming a distinct tube, tube initiation early; A epipetalous; ovary inferior, [2-3], style long[?].
[ESCALLONIALES [BRUNIALES [APIALES [PARACRYPHIALES + DIPSACALES]]]]: ?
[BRUNIALES [APIALES [PARACRYPHIALES + DIPSACALES]]]: ?
Age. Magallón and Castillo (2009: but topology) offer estimates of ca 93.75 m.y. for the crown group, while ages in Beaulieu et al. (2013a) are ca 93 m.y.. Note that many estimates of stem-group ages for Bruniales - implicitly the age of this node - are based on very different topologies that that here, and/or ignore the existence of Columelliaceae as sister to Bruniaceae.
Evolution. Divergence & Distribution. Diversification at this node probably occurred in the southern hemisphere (Beaulieu et al. 2013a). Bruniales are another old, species poor but morphologically quite diverse clade that is placed along the spine of the asterid II clade.
BRUNIALES Dumortier Main Tree.
Plant woody, evergreen; iridoids?; nodes 1:1; flowers polysymmetric; anthers basifixed; G position?; ovules weakly crassinucellate. - 2 families, 14 genera, 79 species.
Age. The crown group age is around 110 m.y. old (Bremer et al. 2004).
Note: Possible apomorphies are in bold. However, the actual level at which many of these features, particularly the more cryptic ones, should be assigned is unclear. This is partly because many characters show considerable homoplasy, in addition, basic information for all too many is very incomplete, frequently coming from taxa well embedded in the clade of interest and so making the position of any putative apomorphy uncertain. Then there is the not-so-trivial issue of how ancestral states are reconstructed...
Phylogeny. Bruniaceae are sister (1.0 Bayesian p.p.) to Columelliaceae in many analyses in Winkworth et al. (2008a), although not when coding chloroplast sequences were used alone, while Soltis et al. (2011) found strong support for this clade only when mitochondrial genes were removed from the analysis. Both palynology and wood anatomy had suggested a relationship between Columellia and Desfontainia (ex Loganiaceae) (Mennenga, in Leeuwenberg 1980), and this was strongly supported by rbcL and other data (see B. Bremer et al. 1994; Backlund & Bremer 1997; Bell et al. 2001). All things considered, the circumscription adopted here seems reasonable.
For the positions of this and the other smaller clades along the asterid II spine, which are now mostly settling down, see (Escalloniales.
Chemistry, Morphology, etc. For more on the inferior/superior ovary distinction in the asterid II clade, see the Asterales page.
Previous Relationships. In the first seven versions of this site (pre April 2008) Columelliaceae s.l. (= [Columelliaceae + Desfontainiaceae]) were placed immediately before the ordinal characterisation of Dipsacales - it seemed to make morphological sense and there was some other evidence for this position.
Includes Bruniaceae, Columelliaceae.
Synonymy: Columelliales Doweld, Desfontainiales Takhtajan
BRUNIACEAE Candolle, nom. cons. Back to Bruniales
Ericoid shrubs, with lignotubers; myricetin +, iridoids?; stomata cyclocytic, orientation transverse; leaves spiral, small, close-set, lamina linear, margins entire, stipules +, often minute, colleter-like (0); leaf blade margins entire, apex mucronate; inflorescence racemose or spicate; flowers often small, (4-merous); (K connate), C often clawed (connate); A (adnate to C), anthers ± elongate; nectary +/0; G ± inferior, ?oblique, placentation apical-axile, style branched to the base, stigma capitate; ovules 2/carpel, micropyle long, integument 9-10 cells across, endothelium 0, hypostase +; fruit achenial or nut-like, single-seeded, K persistent; seed (arillate), coat ?; endosperm type?, haustoria?.
6/81[list]/75. South Africa, almost entirely the Cape Province, also KwaZulu-Natal (map: from Claßen-Bockhoff 2000). [Photo - Flowers.]
Age. Crown-group Bruniaceae are dated to 99.5-59.7 m.y.a. (Quint & Claßen-Bockhoff 2008).
There is a striking similarity between the flowers of Actinocalyx, from the Upper Cretaceous (Santonian/Campanian) ca 83.6 m.y.a. of Sweden, and those of Bruniaceae (Hall 1987).
1. Linconieae Quint & Claßen-Bockhoff
Stomata with cuticular rim; petals hard in texture; anthers sagittate, apically connate, with sterile tip; (G ); (fruits with two seeds); n = ?
1/3. The Cape.
[Audouineae + Brunieae]: (styles also connate); x = 11.
2. Audouineae Niedenzu
(Stomata with cuticular rim); (flowers single; inflorescence involucrate); anther thecae parallel, connate and attached to the connective their entire length; (pollen 4-5-colpate); (G [1, 3]); (ovules to 8/carpel); n = 11.
2/14. Southwestern part of the Western Cape.
3. Brunieae Quint & Claßssen-Bockhoff
(Lignotubers 0); inflorescence capitate, (involucrate), (with terminal flower and development centrifugal), (flowers single), etc.; anthers versatile, thecae (to rotund); (pollen to 10-colporate); (G ), (superior); ovules 1(-10)/carpel; (fruit with fleshy accrescent K), (dehiscent, also splitting adaxially); (seeds arillate); n = 22, 23.
3/64. Brunia (37). Esp. the Western Cape (Eastern Cape; KwaZulu-Natal).
Synonymy: Berzeliaceae Nakai
Evolution. Divergence & Distribution. The three main clades (tribes) had all diverged by 33.7-20.2 m.y.a., yet much of the diversification within them has occurred within the last 18-3 m.y. (Quint & Claßen-Bockhoff 2008).
Pollination Biology & Seed Dispersal. Myrmechory occurs in this clade (Lengyel et al. 2010).
Chemistry, Morphology, etc. Bruniaceae are poorly known. The plant is reported to be scented and the leaf apex has suberised cells produced by a localised cork cambium, hence the black tip (Carlquist 1990a). The corolla "tube" is at least sometimes formed by adnation of the filaments to adjacent free petals, and the petals are developmentally initally free (Quint & Claßen-Bockhoff 2006b). The androecium is often weakly monosymmetric, the abaxial pair of stamens being larger than the others. Gynoecial variation is considerable; in genera like Berzelia where there is only a single carpel (really pseudomonomery?), there is only a single locule, ovule and style. There are only one or two layers of parietal cells.
Some information is taken from from Saxton (1910: no endothelium shown) and Mauritzon (1939a), both embryology, Jay (1968a: chemistry), Hall (1988: pollen), Dahlgren and van Wyk (1988), Gregory (1998: anatomy), Endress and Stumpf (1991), Claßen-Bockhoff (2000: detailed discussion of inflorescences), and Quint and Claßen-Bockhoff (2006b: floral ontogeny); for wood anatomy, see Carlquist (1978b).
Phylogeny. The phylogenetic stucture [Linconieae [Audoinieae + Brunieae]] is strongly supported (Quint & Claßen-Bockhoff 2006a).
Classification. Claßssen-Bockhoff et al. (2011) propose a tribal classification based on the phylogeny by Quint and Claßssen-Bockhoff (2006a). For a somewhat dated monograph, see Pillans (1947).
Previous Relationships. Bruniaceae have often been linked with the South African Grubbiaceae, here in Cornales (see Hall 1987 for some references), but the similarities between the two probably reflect the fact that they are ericoid shrubs growing in similar habitats.
COLUMELLIACEAE D. Don, nom. cons. Back to Bruniales
Cork cambium deep-seated; pericyclic fibres 0; petiole bundles arcuate; bud without scales; leaves opposite, petiole bases meeting, lamina margins toothed; inflorescence terminal, cymose; flowers medium-sized; anther connective well-developed, thecae attached their entire length; ovules many/carpel, endothelium poorly developed; K persistent in fruit; seeds many, anticlinal exotestal cells much thickened, with plasmodesmata.
2[list]/5. Costa Rica to Chile, montane in the tropical part of this area.
Age. These two genera diverged around 64 m.y.a. (Bremer et al. 2004).
Columellia D. Don
Shrubs or trees; plant bitter tasting, iridoids 0; styloids +; central petiole bundle much the largest; cuticle waxes as tubules; lamina (with glands on lower surface), teeth glandular (0); flowers (4-8-merous); K ± valvate; A 2, latrorse, thecae semicircular, connective broad, expanded; tapetum amoeboid; G largely inferior, placentation intrusive parietal or lobed-axile, stigma with two broad lobes, almost cup-like; ovules ?lacking parietal tissue; fruit septicidal and part loculicidal, opening down the sides; exotestal cells elongated; endosperm type?; n = ?
1/4. S. Colombia to Bolivia, in the Andes (map: from Brizicky 1961). [Photo - Flower.]
Desfontainia Ruíz & Pavón
Shrubs; route I secoiridoids +, tannin 0; scattered sclereids in the pericyclic position; lamina vernation conduplicate, teeth spiny, colleters +; inflorescence usu. single-flowered; K connate at base, C contorted; A adnate in throat, filaments stout; G [5(-7)], opposite petals, placentation axile but apically parietal, stigma only slightly expanded; ovule with integument 6-9 cells across; fruit a berry; exotestal cells polygonal, outer walls pectic, other walls, especially anticlinal, lignified; endosperm haustoria small; n = 7.
1/1: Desfontainia spinosa. Costa Rica to Chile. [Photo - Flower.]
Symonymy: Desfontainiaceae Pfeiffer
Evolution. Divergence & Distribution. Another old, species-poor but morphologically quite diverse group that occurs in South America and is in the asterid II clade....
Chemistry, Morphology, etc. The intervascular pits of Desfontainia are scalariform or circular and bordered, not vestured. All the cells in even the young stem are slightly lignified. Myricetin?
The two stamens of Columellia are the adaxial pair and have latrorse, semicircular thecae attached their length to an expanded connective; the anthers are described as being extrorse by Backlund and Donoghue (1996). Although both Desfontainia and Viburnum have similar, smooth pollen orbicules, these are also quite widely distributed in Gentianales, at least (Vinckier & Smets 2002). Maldonado de Magnano (1986a) suggests that the ovules of Desfontainea are weakly crassinucellate, with a single layer of nucellar cells between the megaspore and the nucellar epithelium; an endothelium is at most poorly developed, and there is a large haustorial suspensor.
For Columellia information was taken from Hasselberg (1937), Stern et al. (1969: anatomy), Backlund and Donoghue (1996: general), and Gregory (1998: anatomy), for waxes, see Theisen and Barthlott (1994) and Fehrenbach and Barthlott (1988: cuticle platelets as ribbons and rodlets): Further data from: Zak & Jaramillo 3266. For Desfontainia information was taken from Backlund and Donoghue (1996) and Hasselberg (1937): Further data from: Qin 710 and Zarucchi et al. 5195.
Previous Relationships. The relationships of Columelliaceae have long been uncertain; the family was placed in Rosales by Cronquist (1981) and in Hydrangeales by Takhtajan (1997). Desfontainea has usually been included in the heterogeneous Loganiaceae - and so entirely unrelated.