Australian Tropical Rainforest Plants - Online edition

Rhynchosia acuminatissima Miq.


Slender Vine
Click/tap on images to enlarge
Leaves and Flowers. © CSIRO
Fruit and seeds. CC-BY J.L. Dowe
Scale bar 10mm. © CSIRO
1st leaf stage, cotyledons absent. © CSIRO
10th leaf stage. © CSIRO
Family

Miquel, F.A.W (1855) Flora van Nederlandsch Indie 1(1): 171. Type: Java, in de prov. Bandong door ZOLLINGER ontdekt.

Stem

A slender vine not exceeding a stem diameter of 2 cm.

Leaves

Leaves and twigs may emit an unpleasant odour when crushed, the odour resembles that of cat's (Felis catus) urine. All plant parts densely clothed in soft golden or yellowish hairs. Middle leaflet blade about 6.5-13 x 4-10.5 cm, pulvinate, stalk about 1.5-3.5 cm long. Lateral leaflets about 6-13 x 3-8.5 cm, stalks about 0.3-0.7 cm long. Lateral leaflets oblique at the base. Compound leaf petiole about 4-5 cm long. Underside of the leaflet blades clothed in small yellowish glands. Stipules lanceolate, about 3-13 mm long, caducous. Stipels about 3-4 mm long.

Flowers

Flowers about 10 x 7 mm on pedicels about 4 mm long. Calyx lobes unequal in size, one lobe about 2 mm long, two lobes about 1 mm long and two about 0.5 mm long. Petals: standard about 7-11 x 8 mm; wings about 10 mm long; keel about 11 mm long. Stamens 10, the filaments of nine fused to form a tube open on one side. One stamen free. Stamens about 10-11 mm long. Pollen yellow. Ovary pubescent, about 4-5 mm long. Style about 5-7 mm long, stigma globose.

Fruit

Fruits about 17-20 x 4-6 mm, outer surface clothed in velvety hairs and globose resinous glands. Pods constricted between the seeds. Calyx persistent at the base of the fruit, style persistent at the apex. Seeds ellipsoid, about 4-5 x 5-6 mm. Testa bright metallic blue. Hilum about 1.5-2 mm long. Radicle about 1 mm long.

Seedlings

First pair of leaves cordate to triangular, leaf blade about 23-26 x 20-21 mm, apex acuminate, base cordate or truncate. Petioles about 10-15 mm long. Stipules about 2-3 mm long. At the tenth leaf stage: lateral leaf blades +/- triangular, about 5 x 3 cm, apex acuminate, base truncate and oblique, leaflet stalks about 0.3 cm long. Stalk of the middle leaflet much longer than those of the lateral leaflets. Compound leaf petiole about 4 cm long. Stems and petioles clothed in pale-coloured +/- erect hairs. Roots nodular and emitting a bean-like (Phaseolus vulgaris) odour when crushed or broken. Stems twining after the tenth leaf stage. Seed germination time 13 days.

Distribution and Ecology

Occurs in CYP, NEQ, CEQ and southwards as far as north-eastern New South Wales. Altitudinal range in northern Australia from near sea level to 1000 m. Grows in monsoon forest, lowland and upland rain forest on the drier and more seasonal sites. Also occurs in New Guinea.

Natural History & Notes

This species is of no grazing significance. Hacker (1990).

Synonyms
Rhynchosia cunninghamii Benth., Flora Australiensis 2: 266(1864), Type: Qld, Endeavour river, Banks and Solander; N.E. coast, A. Cunningham; Moreton Bay, C. Stuart; Mount Elliott and Thozets Creek, Fitzalan, Dallachy.
RFK Code
2530
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