Australian Tropical Rainforest Plants - Online edition

Paspalum conjugatum P.J.Bergius

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Herbarium specimen. © CSIRO

Bergius, P.J. (1772) Acta Helvetica, physico mathematico-anatomico botanico medica : 129. Type: Habitat in Surinamo.

Common name

Johnston river Grass; Yellow Grass; Sour Grass


Perennial with leafy stolons with alternating elongated and bunched internodes. Culms erect, 20-100 cm tall, nodes glabrous with remains of old leaf sheaths. Lateral branches sparsely branched. Stems glabrous and rooting at the nodes.


Leaf blades 11-18 x 1-1.2 cm, mainly glabrous except for a few hairs along the margins, main vein prominent on abaxial surface. Leaf sheath 3-4 cm long, hairy at the top, parchment-like further down. Ligule a membrane 1 mm long with long dense hairs behind it.


Inflorescence usually composed of two secund spikes, each about 60-100 mm long. Glands at base of raceme well-developed, very hairy. Spikelets solitary, pedicellate 0.3-0.5 mm long and in 2 rows below the rachis, markedly ciliate on the margins, cream to creamy-green, flat, about 1 mm long. Rachis prominently winged. Lower glume absent. Upper glume with a few fine hairs along the upper margin, obscurely 3 veined. Lemna glabours. Anthers yellow. Styles 2. Stigmas white, plumose.


Fruits arranged in two rows below the inflorescence branches. Individual fruits about 1.5 x 1 mm, flattened with fimbriate margins. Embryo small. Seeds ca. 1 x 0.8 mm, testa surface smooth and glossy.


Features not available.

Distribution and Ecology

An introduced species in WA, NT, CYP, NEQ, CEQ and southwards to north-eastern New South Wales. Altitudinal range from near sea level to 960 m. Grows in disturbed and open areas and along tracks and roads in rainforest, vineforest, Melaleuca forest and woodland. Also from Africa, Temperate Asia, Tropical Asia, New Guinea, Pacific Islands, North America and South America.

Natural History & Notes

Common and aggressive weed in pasture land.

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