Viminaria Sm.

Scientific Description

Family Papilionaceae. Mirbelieae.

Sometimes included in Leguminosae.

Habit and leaf form. Shrubs (with pendulous, rushlike branches); evergreen. Switch-plants; phyllodineous. Leaves well developed to much reduced. Plants unarmed. Plants with neither basal nor terminal concentrations of leaves; to 2–5 m high. Xerophytic. Phyllodes terete (slender, up to 30 cm long); linear; unarmed. Leaves medium-sized to large; alternate; spiral; with blades (rarely, then with reduced leaflets), or bladeless (mostly); non-sheathing; when laminate, compound; epulvinate; when laminate, unifoliolate to ternate. Leaflets when present, 1–3; not stipellate. Leaf blades centric. Leaves ligulate; with stipules. Stipules intrapetiolar; small, triangular. Stem anatomy. Secondary thickening developing from a conventional cambial ring.

Reproductive type, pollination. Fertile flowers hermaphrodite. Unisexual flowers absent. Plants hermaphrodite. Floral nectaries present. Nectar secretion from the disk. Entomophilous.

Inflorescence and flower features. Flowers aggregated in ‘inflorescences’; not crowded at the stem bases; not in pairs subtended by a common bract; in racemes, or in panicles. Inflorescences compound; terminal; pendent; long, loose, terminal, small-flowered racemes or ‘panicles’. Flowers pedicellate (the pedicels 1–4 mm long); bracteate (the bracts narrowly triangular, 1–3 mm long); ebracteolate; small to medium-sized (7–10 mm long); very irregular; zygomorphic. The floral asymmetry involving the perianth, or involving the perianth and involving the androecium. Flowers papilionaceous; 5 merous; tetracyclic. Floral receptacle not markedly hollowed. Free hypanthium present, or absent. Hypogynous disk present; intrastaminal. Perianth with distinct calyx and corolla; 10; 2 -whorled; isomerous. Calyx present; 5; 1 -whorled; gamosepalous; lobed; toothed (the lobes triangular, acute). Calyx lobes markedly shorter than the tube. Calyx imbricate, or contorted; exceeded by the corolla; regular; non-fleshy; persistent; with the median member anterior. Calyx lobes triangular (about 1 mm long). Corolla present; 5; 1 -whorled; appendiculate, or not appendiculate. Standard not appendaged. Corolla polypetalous, or partially gamopetalous. Probably 2 of the petals joined. The joined petals anterior (constituting the keel). The wings of the corolla free from the keel; not laterally spurred. Standard ‘normally’ developed; broad, emarginate. Keel about equalling the wings (slightly curved); not long-acuminate/beaked (blunt); neither coiled nor spiralled; not bent and beaked. Corolla imbricate; yellow (standard and wings), or orange to red (keel); deciduous. Petals long clawed. Androecial members definite in number. Androecium 10. Androecial sequence not determinable. Androecial members free of the perianth; all equal to markedly unequal; free of one another; 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. Anthers separate from one another to connivent; all alike; dorsifixed; versatile, or non-versatile; dehiscing via pores, or dehiscing via longitudinal slits; latrorse, or 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 filiform. Style glabrous. Stigmatic tissue terminal. Carpel 2 ovuled. Placentation marginal. Ovules arillate.

Fruit and seed features. Fruit aerial; 4–6 mm long; sessile; non-fleshy; not hairy (glabrous, finely reticulate). The fruiting carpel indehiscent; a legume. Pods somewhat elongated (ovoid, ellipsoid or obovoid); not triangular; not becoming inflated; somewhat compressed to terete; not constricted between the seeds; wingless. Fruit 1 celled; 1–2 seeded. Seeds not mucous; small (about 3.5x2 mm); arillate. Cotyledons 2. Embryo bent (radicle inflexed). Testa non-operculate; smooth; homogeneous in colour. Micropyle zigzag, or not zigzag.

Physiology, biochemistry. Photosynthetic pathway: C₃.

Geography, cytology, number of species. Native of Australia. Endemic to Australia. Australian states and territories: Western Australia, South Australia, Queensland, New South Wales, and Victoria. Eremaean Botanical Province and South-West Botanical Province. 2n=18. A genus of 1 species; 1 species in Western Australia; V. juncea; 0 endemic to Western Australia.