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Scale bar 10mm. Copyright CSIRO
Habit, leaves, flowers and fruit. Copyright CSIRO
Cotyledon stage, epigeal germination. Copyright CSIRO
10th leaf stage. Copyright CSIRO
Rivina humilis L.
Linnaeus, C. von (1753) Species Plantarum 2: 121. Type: Habitat in Caribaeis, Jamaica, Barbados..
Rivina humilis var. glabra (L.) H.Walter, Das Pflanzenreich Heft 39: 105(1909), Type: ?. Rivina laevis L., Mantissa Plantarum: 41(1767), Type: Habitat in America. Rivina glabra L., Species Plantarum 1: 122(1753), Type: West Indies. Fide Hewson (1984).
Usually flowers and fruits as a shrub about 1 m tall but can flower and fruit when much smaller.
Leaf blades about 4-12 x 1.5-4 cm, petioles about 1-3.5 cm long. Leaf blade quite thin, wilting quickly when picked. Twigs glabrous, longitudinally grooved, rather pithy. Scattered pale-coloured hairs usually present along the midrib on the underside of the leaf blade. Petiole with two rows of glandular hairs on the upper surface.
Racemes +/- erect, glabrous, about 4-12 cm long, pedicels about 2-3 mm long at anthesis, subsequently elongating. Tepals about 2-2.5 mm long, glabrous. Anthers glabrous. Ovary subglobose, glabrous, style short with an extension running down the side of the ovary.
Cotyledons orbicular to almost cordate, glabrous, about 9-11 mm diam, petiole about 8-10 mm long, almost as long as the cotyledon. At the tenth leaf stage: leaf blade lanceolate or broadly lanceolate, petiole almost as long as the leaf blades. Upper surface of the petiole, near its junction with the leaf blade, densely clothed in short, glandular (?) hairs. Petiole grooved on the upper surface.
Distribution and Ecology
An introduced species originally from tropical America, now naturalized in CYP (Torres Strait Islands), NEQ and southwards as far as north-eastern New South Wales. Altitudinal range from near sea level to 900 m. Usually a weed associated with man-made or modified vegetation types but also grows in disturbed areas in lowland and upland rain forest and monsoon forest. Also found in closed vegetation types near the sea. Also occurs as a pantropic weed.
All plant parts are poisonous. Austin, D. F. 1998. Poisonous Plants of Southern Florida. (http://www.fau.edu/divdept/science/envsci/poison- pl.html)
This species may have medicinal properties and it is regarded as poisonous. (http://squid2.laughingsquid.net/hosts/herbweb.com /herbage/A22956.htm)
Herb (herbaceous or woody, under 1 m tall)
Shrub (woody or herbaceous, 1-6 m tall)