Australian Tropical Rainforest Plants - Online edition

Mitracarpus hirtus (L.) DC.

Herb (herbaceous or woody, under 1 m tall)
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Leaves and flowers. © CSIRO
Habit, leaves and flowers. © CSIRO
Herbarium specimen. © DERM
Cotyledon stage, epigeal germination. © CSIRO
10th leaf stage. © CSIRO
Scale bar 10mm. © CSIRO

Candolle, A.P. de (1830) Prodromus 4: 572.


Annual herbs with erect or spreading stems, 20-60 cm long, pubescent with scabrid hairs and appressed hairs, usually villous on the angles, older epidermis peeling.


Leaves elliptic to elliptic-lanceolate, 2-6 x 0.5-1.5(-2) cm, adaxial surface scabrid to glabrous, abaxial surface glabrous except puberulent along veins and usually scabrid near margins, subsessile, stipules 1-3 mm long, with 6-9(-15) setae 1-5 mm long, their margins ciliate, often tipped with colleters.


Flowers in dense axillary clusters, stipule-derived bracteoles filamentous, 1-2 mm long; hypanthium 1-1.4 mm long; calyx lobes 4, 2 of them oblong-lanceolate, with hyaline margins, 1.3-2.3(-3) mm long, the other 2 deltate-lanceolate, 0.5-1.5 mm long, pubescent in lower part and ciliate; corolla white, 2-3 mm long. Anthers exserted.


Capsules subglobose, ca. 1 mm long with the persistent sepals more than three times as long as the fruit. Seeds pale yellowish brown, ellipsoid-rectangular, compressed, 0.8-0.9 mm long, the dorsal face resembling a rectangle with a square portion removed from each corner, ventrally separated into 4 discrete areas by 4 impressed cross lines arising at the hilum; testa reticulate-foveolate.


Seed germination time 11 to 42 days. Cotyledons +/- orbicular, about 2.5-4 mm diam. First pair of leaves ovate, mainly glabrous, stipules present, interpetiolar. At the tenth leaf stage: leaf blade ovate or elliptic, +/- sessile. Upper surface strigose, lower surface pubescent. Stipules interpetiolar with several tooth-like projections. Stems 4-angled, hairy.

Distribution and Ecology

Occurs in NT, CYP, NEQ, CEQ and as far south as Brisbane. Altitudinal range from near sea level to 1050 m. Grows in disturbed places and along roads and tracks through rainforest, Eucalypt forest, deciduous vine thicket and various types of woodland.

Natural History & Notes

A common roadside weed and a weed of cultivation.

Spermacoce hirta L., Species Plantarum Edn. 2 1: 148(1762).
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