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Scale bar 10mm. Copyright CSIRO
10th leaf stage. Copyright CSIRO
Cotyledon stage, epigeal germination. Copyright CSIRO
Desmodium tortuosum (Sw.) DC.
Candolle, A.P. de (1825) Prodromus 2: 332. Type: ?.
Hedysarum tortuosum Sw., Prod. Veg. Ind. Occ.: 107(1788), Type: ?.
Florida Beggar-weed; Beggarweed
Usually flowers and fruits as a shrub about 1-2 m tall, occasionally flowers when smaller.
Compound leaf rhachis grooved on the upper surface. Middle leaflet larger than the lateral leaflets. Leaflet blades about 1.8-4.8 x 1-2 cm. Stalk of the middle leaflet grooved on the upper surface and much longer than those of the lateral leaflets. Pulvinus present only on the middle leaflet. Leaflets and petioles clothed in hooked hairs which cause them to adhere to clothing. Stipules narrowly triangular, about 3-6 mm long, longitudinally veined, soon becoming dry and papery.
Calyx about 2.5 mm long. Two calyx lobes fused for most of their length but the other calyx lobes fused for less than half of their length. Corolla about 4 mm long. Stamens 10, the filaments of nine stamens fused to form a tube with the anthers alternately higher and lower. One stamen free or mainly free. Ovary clothed in prostrate hairs, ovules about 6.
Pods about 10-30 mm long, segmented, breaking into 1-seeded nutlets, surface textured with conspicuous venation. Fruits clothed in hooked hairs which cause them to adhere to clothes to some extent but not with any great tenacity. Testa very thin, yellowish, oily. Radicle curved and adjacent to the margins of the cotyledons.
Cotyledons about 8 x 4-4.5 mm, pubescent on both the upper and lower surfaces. First pair of leaves opposite, ovate. At the tenth leaf stage: stem clothed in erect hooked hairs. Stipules triangular, about 6 mm long, apex acuminate. Stipels on the unifoliolate leaves or leaflets, linear about 2 mm long.
Distribution and Ecology
An introduced species originally from tropical America but now pantropic, naturalized in WA, NT, CYP, NEQ and southwards as far as south-eastern Queensland. Altitudinal range in northern Australia from near sea level to 250 m. Grows in open forest but also found along roads and in disturbed areas in lowland rain forest and monsoon forest.
A locally common weed species which has been used for hay. Hacker (1990).
Herb (herbaceous or woody, under 1 m tall)
Shrub (woody or herbaceous, 1-6 m tall)