Family Papilionaceae. Phaseoleae.
Sometimes included in Leguminosae.
Habit and leaf form. Herbaceous climbers; not resinous. Plants unarmed. Perennial. Leaves cauline. Plants with neither basal nor terminal concentrations of leaves. Climbing; stem twiners. Twining anticlockwise. Helophytic, or mesophytic. Leaves medium-sized; not fasciculate; alternate; spiral, or distichous; not decurrent on the stems; ‘herbaceous’, or leathery; not imbricate; petiolate. Petioles wingless. Leaves non-sheathing; not gland-dotted; compound; pulvinate; ternate. Leaves pinnately trifoliolate. Leaves imparipinnate. Leaflets 3; (2–)4–12 cm long. Lateral leaflets opposite. Leaflets stipellate; pulvinate; ovate, or linear; flat; with conspicuous lateral lobes, or without lateral lobes. Leaflet margins flat. Leaf blades dorsiventral; cross-venulate. Leaves with stipules. Stipules intrapetiolar; free of the petiole; free of one another; scaly, or leafy (often cordate or spurred, sometimes peltate); caducous, or persistent. Leaf blade margins not prickly; flat. Leaves without a persistent basal meristem. Leaf anatomy. Hairs present; glandular hairs absent; complex hairs absent. Stem anatomy. Secondary thickening developing from a conventional cambial ring, or anomalous.
Reproductive type, pollination. Fertile flowers hermaphrodite. Unisexual flowers absent. Plants hermaphrodite. Floral nectaries present. Nectar secretion from the disk. Pollination mechanism conspicuously specialized.
Inflorescence and flower features. Flowers aggregated in ‘inflorescences’; not crowded at the stem bases. Inflorescences compound. The terminal inflorescence unit cymose, or racemose. Inflorescences terminal, or axillary; slender pseudoracemes of umbel-like clusters. Flowers shortly pedicellate; bracteate. Bracts deciduous (caducous). Flowers bracteolate. Bracteoles deciduous (caducous). Flowers small to medium-sized; very irregular; zygomorphic. The floral asymmetry involving the perianth and involving the androecium. Flowers papilionaceous (imbricate-descending); basically 5 merous; tetracyclic. Floral receptacle developing a gynophore to with neither androphore nor gynophore. Free hypanthium present, or absent. Hypogynous disk present; intrastaminal. Perianth with distinct calyx and corolla; (9–)10; 2 -whorled; isomerous, or anisomerous. Calyx present; 4, or 5; 1 -whorled; gamosepalous; lobed; blunt-lobed, or toothed, or blunt-lobed and toothed; imbricate; exceeded by the corolla; bilabiate; neither appendaged nor spurred; non-fleshy; persistent; non-accrescent; with the median member anterior. Corolla present; 5; 1 -whorled; appendiculate, or not appendiculate. Standard appendaged, or not appendaged. Corolla partially gamopetalous. 2 of the petals joined, or 4 of the petals joined. The joined petals anterior (or anterior and lateral?). The wings of the corolla not laterally spurred. Standard ‘normally’ developed; not sericeous. Keel conspicuously exceeded by the wings, or about equalling the wings; not long-acuminate/beaked; coiled or spiralled, or neither coiled nor spiralled; not bent and beaked. Corolla imbricate (descending); glabrous abaxially; glabrous adaxially; cream, or yellow, or purple, or violet; deciduous; non-accrescent. Petals clawed. Androecial members definite in number. Androecium 10. Androecial sequence not determinable. Androecial members free of the perianth; markedly unequal (the filaments alternately long and short); coherent; 2 - adelphous (the posterior stamen free of the tube). The staminal tube free from the keel petals. Androecial members 1 -whorled. Androecium exclusively of fertile stamens. Stamens 10; all more or less similar in shape; diplostemonous; both opposite and alternating with the corolla members; filantherous. Anthers separate from one another to connivent; all alike; dorsifixed; versatile, or non-versatile; dehiscing via longitudinal slits; latrorse, or introrse; tetrasporangiate. Pollen shed as single grains. 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 curved, or coiled, or sigmoid. Style terete. Style bearded down one side. Stigmatic tissue lateral. Carpel 3–100 ovuled (i.e. to ‘many’). Placentation marginal. Gynoecium median. Ovary sessile to subsessile. Styles hairy. Ovules funicled; pendulous to ascending; biseriate; arillate, or non-arillate; anatropous, or campylotropous to amphitropous, or hemianatropous.
Fruit and seed features. Fruit aerial; 25–92 mm long; subsessile, or sessile; non-fleshy; hairy, or not hairy; not spinose. The fruiting carpel dehiscent; a legume. Pods much elongated; not triangular; straight, or curved; not becoming inflated; more or less flat, or somewhat compressed, or terete; regularly constricted between adjacent seeds, or irregularly constricted, or not constricted between the seeds; more or less transversely septate between the seeds; wingless; not internally hairy. Valves of the dehisced pod twisted, or not twisted. Fruit 1 celled; elastically dehiscent. Dispersal unit the seed. Fruit 3–50 seeded (to many). Seeds non-endospermic; not mucous; compressed, or not compressed (sometimes cuboid); small; arillate, or non-arillate; not conspicuously hairy. Cotyledons 2; accumbent. Embryo curved, or bent. Testa hard; non-operculate; smooth (or ridged); homogeneous in colour, or conspicuously colour-patterned. Micropyle zigzag, or not zigzag. Seedling. Germination mostly cryptocotylar.
Special features. Calyx limb 4–5 lobed. Upper lip of calyx entire, or lobed; 1 lobed, or 2 lobed. Lower lip of calyx lobed; 3 lobed.
Geography, cytology, number of species. Native of Australia and adventive. 2n=(20)22; ploidy levels recorded 2. A genus of about 150 species; 4 species in Western Australia; V. lanceolata Benth., V. radiata (L.) Wilczek, V. vexillata (L.) A. Rich.