The families of flowering plants
~ Columelliaceae, Loganiaceae.
Habit and leaf form. Glabrous shrubs (with shiny, dark green, prickly, holly-like leaves), or trees (rarely, small); leptocaul. Leaves evergreen; small to medium-sized; opposite; flat; leathery; petiolate; simple; epulvinate. Lamina dissected to entire (holly-like); oblong, or ovate; pinnately veined; cross-venulate. Leaves stipulate to exstipulate. Stipules interpetiolar to intrapetiolar (the small stipules connected by a transverse line). Lamina margins dentate (prickly-dentate and holly-like). Leaf development not graminaceous.
Leaf anatomy. The leaf lamina dorsiventral. Extra-floral nectaries absent. Stomata present; anomocytic. Hairs present, or absent; when present, eglandular. Complex hairs absent. Minor leaf veins without phloem transfer cells.
Axial (stem, wood) anatomy. Young stems cylindrical. Cork cambium present; initially deep-seated (arising near the phloem). Primary vascular tissues in a cylinder, without separate bundles; collateral. Internal phloem absent. Secondary thickening developing from a conventional cambial ring. Primary medullary rays very narrow (predominantly uniseriate, of upright cells). The axial xylem with vessels (narrow, hard to distinguish from the other elements in T.S.).
The wood ring porous. The vessel end-walls very oblique; scalariform (with many bars). The vessels without vestured pits (intervascular pitting partly scalariform, partly rounded and bordered). The axial xylem with tracheids (readily recognisable as such only in mac erated material, in radial rows with the vessels); with fibre tracheids; without libriform fibres. The parenchyma apotracheal (mainly diffuse). Included phloem absent. The wood not storied.
Reproductive type, pollination. Plants hermaphrodite; homostylous.
Inflorescence, floral, fruit and seed morphology. Flowers mostly solitary; axillary (in opposite axils); small to medium-sized; regular to somewhat irregular. The floral irregularity when detectable involving the perianth (the calyx only). Flowers 5 merous; tetracyclic. Free hypanthium absent.
Perianth with distinct calyx and corolla; 10; 2 whorled; isomerous. Calyx 5; 1 whorled; gamosepalous (basally only); blunt-lobed (the oblong lobes ciliate); unequal but not bilabiate, or regular; non-fleshy; persistent; non-accrescent; strongly imbricate. Corolla 5; alternating with the calyx; gamopetalous. Corolla lobes markedly shorter than the tube. Corolla imbricate, or contorted (but not twisted); funnel-shaped, or hypocrateriform to tubular; regular; yellow and red (the tube crimson, the lobes yellow); fleshy.
Androecium 5. Androecial members adnate (in the throat of the corolla); all equal; free of one another; 1 whorled. Androecium exclusively of fertile stamens. Stamens 5; inserted in the throat of the corolla tube; isomerous with the perianth; oppositisepalous; alternating with the corolla members; filantherous (the filaments short and thick). Anthers basifixed; dehiscing via longitudinal slits; introrse. Pollen grains aperturate; 3 aperturate; colporate.
Gynoecium (3–)5 carpelled. Carpels reduced in number relative to the perianth to isomerous with the perianth. The pistil (2–)5 celled (i.e., diminishing from 5 above). Gynoecium syncarpous; eu-syncarpous; superior. Ovary (3–)5 locular, or 1 locular (i.e., becoming unilocular above); sessile. Gynoecium stylate. Styles 1 (the style persistent); apical. Stigmas 1; capitate. Placentation above, where unilocular, parietal (the mushroom-shaped placentas intruding deeply); below, where plurilocular, axile. Ovules differentiated; 15–50 per locule (many); anatropous (?); unitegmic; crassinucellate. Endothelium differentiated. Endosperm formation cellular.
Fruit fleshy; indehiscent; a berry (white or yellow). Dispersal unit the fruit. Seeds endospermic (the endosperm starchy). Embryo well differentiated (but minute). Cotyledons 2. Embryo straight.
Physiology, phytochemistry. Alkaloids present, or absent (only weak positives recorded no isoquinoline alkaloids). Anthraquinones not detected. Verbascosides not detected. Cornoside detected. Iridoids detected; Route I type. Saponins/sapogenins absent.
Geography, cytology. Andes, Costa Rica to Cape Horn. 2n=14. Supposed basic chromosome number of family: 7. Ploidy levels recorded: 2.
Taxonomy. Subclass Dicotyledonae; Tenuinucelli. Dahlgrens Superorder Corniflorae; Dipsacales (re-assigned). Cronquists Subclass Rosidae; Rosales. APG 3 core angiosperms; core eudicot; Superorder Asteranae; campanulid; Order Bruniales (as a synonym of Columelliaceae).
Species 1. Genera 1; only genus, Desfontainia.
General remarks. See Leeuwenberg (1980); but Desfontainea seems related to Dipsacales rather than Gentianales in terms of both the available descriptive data and rbcL sequence analyses (cf. Bremer et al., 1994). It differs from our description of Columelliaceae (q.v.) in 16 rather conspicuous floral morphological characters, as well as in yielding iridoids. The nearest neighbour as assessed from the present descriptions is Caprifoliaceae.
Economic uses, etc. A cultivated ornamental.
Illustrations. • Desfontainia spinosa: Hook. Ic. Pl. 1 (1837). • Desfontainia spinosa: Bot. Mag. 80 (1854).
We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, distributions of character states within any set of taxa, geographical distribution, genera included in each family, and classifications (Dahlgren; Dahlgren, Clifford, and Yeo; Cronquist; APG). See also Guidelines for using data taken from Web publications.
Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 1992 onwards. The families of flowering plants: descriptions, illustrations, identification, and information retrieval. Version: 12th September 2017. delta-intkey.com/angio’.