Excluding Antoniaceae, Buddlejaceae, Plocospermataceae, Potaliaceae, Spigeliaceae, Strychnaceae
Habit and leaf form. Trees, shrubs, herbs, and lianas. Self supporting, or climbing. Mesophytic. Leaves opposite; connate, or not connate; simple. Lamina entire; pinnately veined; cross-venulate. Leaves more or less stipulate, or exstipulate (but then the opposing bases connected by lateral lines). Stipules interpetiolar (or represented by a stipular sheath); free of one another, or concrescent; often much reduced. Domatia recorded (Coinochlamys); represented by pockets.
Leaf anatomy. Mucilaginous epidermis present, or absent.
Lamina dorsiventral, or isobilateral. The mesophyll with sclerencymatous idioblasts, or without sclerenchymatous idioblasts.
Stem anatomy. Cork cambium present; initially deep-seated, or superficial. Nodes unilacunar (with 1-several traces), or tri-lacunar, or multilacunar. Primary vascular tissue bicollateral. Internal phloem present. Secondary thickening developing from a conventional cambial ring, or anomalous; via concentric cambia. `Included' phloem present, or absent. Xylem with tracheids, or without tracheids; with fibre tracheids, or without fibre tracheids; with libriform fibres, or without libriform fibres; with vessels. Vessel end-walls simple (usually), or scalariform. Vessels with vestured pits. Wood parenchyma apotracheal, or paratracheal (very variable, sometimes very rare or absent).
Reproductive type, pollination. Hermaphrodite.
Inflorescence, floral, fruit and seed morphology. Flowers aggregated in `inflorescences' (usually), or solitary; in cymes (when not solitary). The terminal inflorescence unit usually cymose. Inflorescences terminal; cymes. Flowers bracteate; bracteolate; regular; 4-5 merous; cyclic; tetracyclic. Hypogynous disk small or absent.
Perianth with distinct calyx and corolla; 8-10; 2 whorled; isomerous. Calyx 4-5; 1 whorled; gamosepalous; bilabiate; imbricate; when K 5 with the odd member anterior. Corolla 4-5; 1 whorled; gamopetalous; imbricate, or contorted (rarely); regular.
Androecium (1-)4-5. Androecial members adnate (epipetalous); free of one another; 1 - whorled. Androecium exclusively of fertile stamens. Stamens (1-)4, or 5; reduced in number relative to the adjacent perianth to isomerous with the perianth; oppositisepalous. Anthers dehiscing via longitudinal slits; introrse. Pollen grains aperturate; 3 - aperturate; porate, or colporate.
Gynoecium 2; syncarpous; synstylovarious, or eu-syncarpous; superior, or partly inferior (rarely). Ovary 1 locular, or 2 locular, or 3 locular. Gynoecium median; stylate. Styles 1; attenuate from the ovary; apical. Placentation when unilocular, parietal; usually axile. Ovules in the single cavity when unilocular, 25 (or more); 25 per locule (or more); anatropous, or hemianatropous; unitegmic; tenuinucellate. Endothelium differentiated, or not differentiated. Embryo-sac development Polygonum-type. Polar nuclei fusing prior to fertilization. Antipodal cells formed; 3; not proliferating; ephemeral. Endosperm formation cellular. Endosperm haustoria present; chalazal and micropylar. Embryogeny onagrad.
Fruit non-fleshy; dehiscent; a capsule. Capsules septicidal, or loculicidal, or valvular. Seeds endospermic; winged, or wingless. Cotyledons 2. Embryo straight (usually), or curved.
Seedling. Germination phanerocotylar.
Physiology, biochemistry. Not cyanogenic. Alkaloids present (mostly), or absent. Iridoids recorded; seco-compounds. Proanthocyanidins absent. Ellagic acid absent. Saponins/sapogenins present, or absent. Aluminium accumulation not found.
Geography, cytology. Temperate (a few), or sub-tropical to tropical. Pantropical, and a few warm temperate.
Taxonomy. Subclass Dicotyledonae; Tenuinucelli. Dahlgren's Superorder Gentianiflorae; Gentianales. Cronquist's Subclass Asteridae; Gentianales. Takhtajan's Subclass Asteridae; Gentiananae; Gentianales. Species 130. Genera 6; Gelsemium, Geniostoma, Labordia, Logania, Mostuea, Polypremum.
Illustrations. logan555.gif
Additional, to be intercalated. Stipules with colleters (secreting mucilage), or without colleters.
