The families of flowering plants
Habit and leaf form. Tall, glabrous herbs (with the habit of Cannabis). Perennial. Leaves alternate; petiolate; non-sheathing; compound; pinnate. Lamina pinnately veined; cross-venulate. Leaves exstipulate. Lamina margins dentate. Domatia occurring in the family; manifested as pockets.
Leaf anatomy. The leaf lamina dorsiventral. Stomata present; mainly confined to one surface (abaxial); anomocytic. Hairs present and absent (?). Complex hairs present (shaggy, each with a multicellular stalk of variable length and a spherical or ellipsoidal, glandular head). The mesophyll without sclerenchymatous idioblasts. Minor leaf veins without phloem transfer cells.
Axial (stem, wood) anatomy. Cork cambium present; initially superficial. Primary vascular tissues in a cylinder, without separate bundles; collateral. Internal phloem absent. Cortical bundles absent. Medullary bundles absent. Secondary thickening developing from a conventional cambial ring. Primary medullary rays wide, or narrow, or wide and narrow.
The wood diffuse porous. The vessels large, or medium to large; solitary, radially paired, and in radial multiples (of 2–3 cells). The vessel end-walls simple. The vessels without vestured pits; without spiral thickening. The axial xylem without fibre tracheids; with libriform fibres; without septate fibres. The fibres without spiral thickening. The parenchyma scarce, paratracheal. The secondary phloem not stratified (but containing groups of fibres when mature). Included phloem absent. The wood not storied. Tyloses present (not abundant).
Reproductive type, pollination. Unisexual flowers present. Plants dioecious, or androdioecious, or polygamomonoecious. Gynoecium of male flowers absent. Pollination anemophilous.
Inflorescence, floral, fruit and seed morphology. Flowers aggregated in inflorescences; in fascicles. Inflorescences crowded fascicles on long, leafy branches.
Perianth sepaline; 3–9. Calyx 3–9 (male flowers), or 3–8 (female and hermaphrodite flowers); polysepalous; members unequal; persistent.
Androecium 3–5 (in hermaphrodite flowers), or 8–25 (in male flowers). Androecial members free of the perianth; free of one another. Androecium exclusively of fertile stamens (or hermaphrodite flowers sometimes with some imperfect stamens?). Stamens 8–25 (male flowers), or 3–5 (hermaphrodite flowers); filantherous (the filaments short). Anthers dorsifixed; dehiscing via longitudinal slits; extrorse; tetrasporangiate. Pollen grains aperturate; 3 aperturate; colporate; 2-celled.
Gynoecium 3–5 carpelled. The pistil 1 celled. Gynoecium syncarpous; synovarious (open at the apex); inferior (ribbed). Ovary 1 locular. Epigynous disk absent. Gynoecium stylate. Styles 3–5 (each deeply bifid). Stigmas dry type; papillate; Group II type. Placentation parietal. Ovules in the single cavity 30–100 (many); anatropous; bitegmic; tenuinucellate. Outer integument contributing to the micropyle. Embryo-sac development Allium-type. Polar nuclei fusing prior to fertilization. Antipodal cells formed; 3; not proliferating; persistent. Synergids pear-shaped. Endosperm formation nuclear. Embryogeny onagrad.
Fruit non-fleshy; dehiscent; a capsule (membranous). Capsules opening apically between the persistent styles. Fruit 30–100 seeded (many seeded). Seeds more or less non-endospermic. Embryo well differentiated (but small). Cotyledons 2 (oily). Embryo straight. Testa coarsely reticulate.
Seedling. Germination phanerocotylar.
Physiology, phytochemistry. Not cyanogenic. Proanthocyanidins absent. Flavonols present; kaempferol and quercetin. Ellagic acid absent. Aluminium accumulation not found.
Geography, cytology. Holarctic. Temperate to tropical. Dry Western Eurasia, dry North America. N = 11.
Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgrens Superorder Violiflorae; Violales. Cronquists Subclass Dilleniidae; Violales. APG III core angiosperms; core eudicot; Superorder Rosanae; fabid. APG IV Order Cucurbitales.
Species 2. Genera 1; only genus, Datisca.
Illustrations. • Le Maout and Decaisne: Datisca cannabina. • Datisca cannabina: Saleem, Fl. of Pakistan (www.eFloras.org, 2017).
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: 5th March 2018. delta-intkey.com/angio’.