Broad-leaved Carpet Grass
Axonopus compressus (Sw.) P.Beauv.
Broad leaved Carpet grass.
Summary:A perennial, stoloniferous, carpet forming, hairless grass. 150-600 mm tall.
Leaves: Hairless but there may be a few hairs where the blade joins the sheath and along the edge of the blade.
Blade - Flat or keeled. Striped. Narrowly egg shaped to parallel sided. 80-250 mm long x 60-120 mm wide. Flattened and folded along the obvious midrib. Rarely with hairs on the upper side, never hairs on the lower side, hairs on the edges.
Ligule - short membranous rim that is flat on top and is usually fringed with fine hairs.
Sheath - flattened, keeled. Striped. Often have a purple tinge. Edges are translucent. Deeply split. Hairless or rarely hairy on the edges.
Auricles - None.
Stems: Slender or in tufts. 1-3 nodes. Nodes are densely hairy.
Flattened. Often purplish. Nodes often hairy.
Flower head:Main axis (rachis) is triangular with concave faces giving 3 distinct lengthwise ridges. Usually 2 or 3 branches, with the upper 2 paired and one longer than the other.
Spikes - 2 or 3 usually (less than 5). No stalk. Slender. Erect or spreading. 40-100 x 1-15 mm.
Flowers: Spikelets - Single, one flowered. Oval to egg shaped. Erect. Green or purplish. Alternate and held close to the stalk. 2.2-3.5 mm long x 1 mm wide.
Florets - The bisexual one is oval to oblong, rounded top, shorter than spikelet.
Glumes - Upper one, oval to egg shaped, 2-4 ribs near the edges, middle is papery.
Palea - The bisexual one is hard, thin and brittle.
Lemma - Empty one similar to the glume. Bisexual one is hard, thin and brittle.
Seeds:2.2-3.5 mm long x 1 mm wide.
Roots:Creeping stems that root at the nodes. Fibrous underground roots. Occasionally forms rhizomes.
Key Characters:No auricles.
Short membranous ligule.
Flattened, keeled, striped, deeply split sheath with translucent edges.
Adapted from J.H. Moore.
October to March.
Seed Biology and Germination:Vegetative Propagules:
Population Dynamics and Dispersal:
Spreads by creeping stems that root at the nodes.
Origin and History:Tropical America.
Introduced as a lawn grass.
Distribution:NSW, QLD, WA.
Courtesy Australia's Virtual Herbarium.
Habitats:Warm moist areas. Intolerant of drought.
Spring and early summer fodder grass.
Detrimental:Weed of other lawns, poor pastures, rotation crops, disturbed areas and grassland.
Management and Control:Thresholds:
Narrow leaved Carpet grass (A. affinis).
Plants of similar appearance:Narrow leaved Carpet grass (Axonopus affinis) has longer, narrower leaves and longer flowering heads and no hairs on the leaves. The fertile lemma is 0.8 x the length of the spikelet whilst in Axonopus compressus it is the same length.
Summer grass (Digitaria sanguinalis) has hairy leaves that distinguish it from Carpet grass.
References:Ciba Geigy (1980) Grass Weeds 1. CIBA GEIGY Ltd, Basle, Switzerland. P10. Diagrams.
Lazarides, M. and Hince, B. (1993). CSIRO handbook of economic plants of Australia. (CSIRO, Melbourne). #153.2.
Marchant, N.G., Wheeler, J.R., Rye, B.L., Bennett, E.M., Lander, N.S. and Macfarlane, T.D. (1987). Flora of the Perth Region. (Western Australian Herbarium, Department of Agriculture, Western Australia). p942.
Collated by HerbiGuide. Phone 08 98444064 or www.herbiguide.com.au for more information.