Tephrosia Pers.

Scientific Description

Family Papilionaceae. Tephrosieae.

Habit and leaf form. Shrubs (or subshrubs), or herbs. The herbs perennial. Leaves cauline. Plants with neither basal nor terminal concentrations of leaves; to 0.2–2 m high. Mesophytic, or xerophytic. Leaves small to large; alternate; spiral; ‘herbaceous’, or leathery; not imbricate; petiolate; non-sheathing; gland-dotted, or not gland-dotted; compound; pulvinate; unifoliolate and ternate (rarely), or pinnate, or palmate (rarely); imparipinnate. Leaflets 3–15. Lateral leaflets opposite. Leaflets not stipellate; pulvinate, or epulvinate; flat, or folded, or rolled; without lateral lobes. Leaflet margins flat. Leaf blades dorsiventral. Leaves with stipules. Stipules intrapetiolar; adnate to the petiole, or free of the petiole; free of one another, or concrescent; various. Leaf blade margins entire. Leaves without a persistent basal meristem. Stem anatomy. Secondary thickening developing from a conventional cambial ring.

Reproductive type, pollination. Fertile flowers hermaphrodite. Unisexual flowers absent. Plants hermaphrodite. Entomophilous.

Inflorescence and flower features. Flowers aggregated in ‘inflorescences’. Inflorescences compound (often), or simple; terminal, or axillary, or leaf-opposed. Flowers pedicellate; bracteate; bracteolate (often, at the base of the pedicel), or ebracteolate. Bracteoles persistent, or deciduous. Flowers small to medium-sized; very irregular; zygomorphic. The floral asymmetry involving the perianth and involving the androecium. Flowers papilionaceous (imbricate-descending, with the posterior petal outside and forming the ‘standard’); 5 merous. Floral receptacle with neither androphore nor gynophore. Free hypanthium present, or absent. Hypogynous disk present, or absent. Perianth with distinct calyx and corolla; 10; 2 -whorled; isomerous. Calyx present; 5; 1 -whorled; gamosepalous; five lobed; imbricate, or valvate; exceeded by the corolla; bilabiate (the upper pair of lobes usually connate higher); persistent; non-accrescent; with the median member anterior. Corolla present; 5; 1 -whorled; appendiculate, or not appendiculate. Standard not appendaged. Corolla partially gamopetalous. 2 of the petals joined (the two ventral petals connivent to form the ‘keel’), or 4 of the petals joined (with the wings adherent to the keel). The joined petals anterior (or anterior and lateral). The wings of the corolla adherent to the keel, or free from the keel; not laterally spurred. Standard ‘normally’ developed; sericeous (outside, supposedly always). Keel incurved; not long-acuminate/beaked; neither coiled nor spiralled; not bent and beaked. Corolla imbricate (descending); white, or orange, or red, or pink, or purple; deciduous. Petals clawed. Fertile stamens present. Androecial members definite in number. Androecium 10. Androecial sequence determinable, or not determinable. Androecial members free of the perianth; all equal to markedly unequal; coherent (the filaments basally connate into a tube); 1–2 - adelphous (9+1, with the tenth, posterior stamen entirely free of the rest, or free except in the middle). The staminal tube free from the keel petals. Androecial members 1 -whorled (although diplostemonous). Androecium exclusively of fertile stamens. Stamens 10; all more or less similar in shape; diplostemonous; both opposite and alternating with the corolla members. Anthers separate from one another, or connivent; all alike; dorsifixed; versatile; dehiscing via longitudinal slits; introrse; tetrasporangiate. Gynoecium 1 carpelled. The pistil 1 celled. Carpels reduced in number relative to the perianth. Gynoecium monomerous; of one carpel; superior. Carpel stylate; apically stigmatic. Style (in-) curved, or bent. Style flattened. Style bearded via an apical tuft, or bearded via an apical ring, or bearded down one side, or hairy but not bearded, or glabrous. Stigmatic tissue terminal. Carpel (1–)3–25 ovuled (to ‘many’). Placentation marginal (along the ventral suture). Gynoecium median (the placenta posterior, on the ventral suture). Ovary sessile. Ovules pendulous to ascending; biseriate; arillate, or non-arillate; anatropous, or campylotropous to amphitropous, or hemianatropous.

Fruit and seed features. Fruit non-fleshy; hairy (usually, often sericeous), or not hairy (rarely glabrous); not spinose. The fruiting carpel dehiscent; a legume. Pods much elongated (linear), or somewhat elongated (rarely ovate or oblong); not triangular; straight, or curved, or twisted; not becoming inflated; more or less flat to somewhat compressed; regularly constricted between adjacent seeds, or irregularly constricted, or not constricted between the seeds; transversely septate between the seeds, or not transversely septate; wingless. Valves of the dehisced pod twisted. Fruit 1 celled. Dispersal unit the seed. Fruit (1–)2–20 seeded. Seeds endospermic, or non-endospermic; not mucous; arillate, or non-arillate. Cotyledons 2; accumbent. Embryo chlorophyllous; curved, or bent. Testa non-operculate. Micropyle zigzag, or not zigzag. Seedling. Germination phanerocotylar, or cryptocotylar.

Physiology, biochemistry. Nitrogen-fixing root nodules present. Aluminium accumulation not found. Photosynthetic pathway: C₃.

Geography, cytology, number of species. Native of Australia. 2n=22. A genus of about 400 species; 39 species in Western Australia.