Sourgrass
Paspalum conjugatum Bergius

Family: - Poaceae.

Names:

Paspalum is from the Greek paspalos meaning millet.

Conjugatum

Sourgrass

Other names:

Bufallograss

Caraboagrass

Hilograss

Johnston River grass

Yellow grass

Summary:

A stoloniferous, tufted, spreading perennial grass to 1000 mm tall with a 2 branched seed head with spikelets on the underside.

Description:

Cotyledons:

One.

Leaves:

Blade - Parallel sided to lance shaped, 80-200 mm long by 3-15 mm wide. Usually hairy on the edges, and hairless or rarely hairy on the upper and lower surfaces.

Ligule - Membranous, flat topped, 1 mm long.

Auricles - None.

Sheath - Hairy on the edges.

Stems:

Spreading to erect, tufted, leafy stolons, 200-1000 mm long, roots at the nodes. Nodes furry, stolon nodes usually very hairy. Rarely branched or bent at the nodes.

Flower head:

Slender raceme at the end of the stem made up of usually 2 or rarely 3 branches, at an angle to each other and curved. Each branch is 40-120 mm long, stalkless or almost stalkless or one with a short stalk. The branch axis is narrowly winged,0.8 mm wide.

Flowers:

Spikelets - Almost circular, 1.2-2 mm long by 1-1.4 mm wide with an acute tip. Often with a fringe of hairs on the edges. Single on very short stalks. In 2 rows. Hairless apart from upper glume.

Florets - Fertile one 1.5 mm long.

Glumes - Lower one absent. Upper one 1.2-2 mm long, 2-3 nerved, with fine white hairs on the edges.

Palea -

Lemma - Lower one, 1.2-2 mm long, 2 nerved, faces away from the seed head axis. Upper lemma not strongly hardened.

Stamens -

Anthers -

Fruit:

Flattened.

Seeds:

Roots:

Fibrous.

Key Characters:

Small, 1.2-2 mm, almost circular spikelets.

Biology:

Life cycle:

Perennial. Flowers in summer and May.

Physiology:

Reproduction:

By seed.

Flowering times:

Summer and winter in WA.

Seed Biology and Germination:

Vegetative Propagules:

Roots from the nodes. Stolons.

Hybrids:

Allelopathy:

Population Dynamics and Dispersal:

Spread mainly by seed with some very local spread by stolons.

Origin and History:

Cosmopolitan. Tropical America.

Distribution:

NSW, NT, QLD, WA.

Habitats:

Wet areas.

Climate:

Tropical.

Soil:

Plant Associations:

Significance:

Beneficial:

Detrimental:

Serious weed of water courses, irrigation channels, orchards, vineyards, sugar cane, turf, roadsides, pastures, rotation crop, perennial crops, grass land and disturbed areas.

Toxicity:

Not recorded as toxic.

Legislation:

None.

Management and Control:

Thresholds:

Eradication strategies:

Apply glyphosate in autumn and spring each year.

Herbicide resistance:

Biological Control:

Related plants:

Paspalum (Paspalum dilatatum)

Plicatulum (Paspalum plicatulum)

Russell River grass (Paspalum paniculatum)

Saltwater Couch (Paspalum distichum)

Saltwater Couch (Paspalum vaginatum)

Scrobic (Paspalum scrobiculatum)

Plants of similar appearance:

Grasses.

References:

Auld, B.A. and Medd R.W. (1992). Weeds. An illustrated botanical guide to the weeds of Australia. (Inkata Press, Melbourne). P51.

Ciba Geigy (1980) Grass Weeds 1. CIBA GEIGY Ltd, Basle, Switzerland. P95. Diagrams.

Harden (1993) Vol. 4, p 466.

Hussey, B.M.J., Keighery, G.J., Cousens, R.D., Dodd, J. and Lloyd, S.G. (1997). Western Weeds. A guide to the weeds of Western Australia. (Plant Protection Society of Western Australia, Perth, Western Australia). P60.

Lamp, C. and Collet, F. (1990). A Field Guide to Weeds in Australia. (Inkata Press, Melbourne).

Lazarides, M. and Hince, B. (1993). CSIRO handbook of economic plants of Australia. (CSIRO, Melbourne). #938.2.

Wheeler (1992). p 1203.

Acknowledgments:

Collated by HerbiGuide. Phone 08 98444064 or www.herbiguide.com.au for more information.