Common name. Phlox Family.
Habit and leaf form. Herbs, or shrubs (sometimes), or trees (Cantua). Annual to perennial; plants with neither basal nor terminal concentrations of leaves. Leaves alternate, or opposite, or whorled (Gymnosteris); when alternate, spiral; petiolate to sessile; simple, or compound; when compound pinnate, or palmate. Leaf blades when simple, dissected, or entire; pinnatifid, or palmately lobed; cross-venulate. Leaves without stipules. Leaf blade margins entire, or serrate, or dentate. Stem anatomy. Nodes unilacunar. Secondary thickening developing from a conventional cambial ring.
Reproductive type, pollination. Fertile flowers hermaphrodite. Unisexual flowers absent. Plants hermaphrodite.
Inflorescence and flower features. Flowers solitary (sometimes), or aggregated in ‘inflorescences’; in cymes, or in heads, or in corymbs. The terminal inflorescence unit cymose. Inflorescences cymes or corymbs, sometimes condensed into heads; with involucral bracts, or without involucral bracts; pseudanthial, or not pseudanthial. Flowers bracteolate, or ebracteolate; regular (usually), or somewhat irregular; when irregular, slightly zygomorphic (then slightly bilabiate); 5 merous; cyclic; tetracyclic. Free hypanthium absent. Hypogynous disk present; intrastaminal; of separate members, or annular. Perianth with distinct calyx and corolla; 10; 2 -whorled; isomerous. Calyx 5; 1 -whorled; gamosepalous; five blunt-lobed; imbricate, or valvate; bilabiate to regular; persistent. Corolla 5; 1 -whorled; gamopetalous; usually contorted; campanulate, or funnel-shaped, or hypocrateriform; bilabiate to regular. Androecium 5. Androecial members adnate (epipetalous); free of one another; 1 -whorled. Androecium exclusively of fertile stamens. Stamens 5; isomerous with the perianth; oppositisepalous; all alternating with the corolla members. Anthers dehiscing via longitudinal slits; tetrasporangiate. Gynoecium (2–)3(–5) carpelled. The pistil (2–)3(–5) celled. Carpels reduced in number relative to the perianth, or isomerous with the perianth. Gynoecium syncarpous; synstylovarious; superior. Ovary plurilocular; (2–)3(–5) locular. Gynoecium median. Ovary sessile. Gynoecium stylate. Styles 1 (filiform). Stigmas (2–)3(–5); (2–)3(–5) - lobed. Placentation axile. Ovules 1–50 per locule (to ‘many’); sessile; apotropous; anatropous.
Fruit and seed features. Fruit non-fleshy; dehiscent (usually), or indehiscent; a capsule (usually), or capsular-indehiscent. Capsules usually loculicidal. Seeds endospermic. Endosperm oily. Cotyledons 2. Embryo chlorophyllous (2/3), or achlorophyllous (3 species of Polemonium); curved (slightly), or straight. Seedling. Germination phanerocotylar.
Physiology, biochemistry. Aluminium accumulation not found. Photosynthetic pathway: C3.
Geography, cytology, number of species. Holarctic and Neotropical. World distribution: widespread, but lacking (though often introduced) in Africa, Southern and Southeast Asia Malaysia, Australia and Eastern South America. X = 6, 7, 8, 9. 300 species.