Australian Tropical Rainforest Plants - Online edition

Desmodium tortuosum (Sw.) DC.


Weed
Herb (herbaceous or woody, under 1 m tall)
Shrub (woody or herbaceous, 1-6 m tall)
Click/tap on images to enlarge
Scale bar 10mm. © CSIRO
10th leaf stage. © CSIRO
Cotyledon stage, epigeal germination. © CSIRO
Family

Candolle, A.P. de (1825) Prodromus 2: 332.

Common name

Florida Beggar-weed; Beggarweed

Stem

Usually flowers and fruits as a shrub about 1-2 m tall, occasionally flowers when smaller.

Leaves

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.

Flowers

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.

Fruit

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.

Seedlings

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. Seed germination time 11 to 14 days.

Distribution and Ecology

An introduced species originally from tropical America but now pantropic, naturalised in WA, NT, CYP, NEQ, CEQ 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.

Natural History & Notes

A locally common weed species which has been used for hay. Hacker (1990).

Synonyms
Hedysarum tortuosum Sw., Prod. Veg. Ind. Occ. : 107(1788).
RFK Code
3124
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