Rat tail grass

Sporobolus africanus

This species is widely naturalised in Australia, particularly in the southern and eastern parts of the country. It is most common in the coastal regions of Victoria, New South Wales and southern Queensland, and is also reasonably common in south-eastern South Australia and south-western Western Australia. Scattered populations occur in Tasmania, the ACT, the Northern Territory and northern Queensland. Also naturalised on Lord Howe Island and Norfolk Island, in New Zealand, and in other parts of the Pacific (i.e. in French Polynesia, Niue and Hawaii). A weed of lawns, footpaths, parks, roadsides, disturbed sites, waste areas, swamps, grasslands, open woodlands and pastures in temperate, sub-tropical and occasionally also tropical regions. It is particularly common in areas with compacted soils.

An upright and tufted long-lived grass with wiry flowering stems usually growing 15-50 cm tall. Its long and narrow leaf blades (6-40 cm long and 1-4 mm wide) may be flat or somewhat rolled. Its seed-heads are also very thin and elongated in appearance (6-35 cm long and 4-7 mm wide). They have many short branches (10-20 mm long) that are held closely to the main stem. Each of these branches bears numerous small flower spikelets (2-2.8 mm long). An upright (i.e. erect) and tufted or tussocky long-lived (i.e. perennial) grass usually growing 15-50 cm tall, but occasionally reaching up to 110 cm in height. The hairless (i.e. glabrous) flowering stems (i.e. culms) are slender (1.5-3 mm thick), but somewhat wiry, and are usually not branched.

The alternately arranged leaves are very thin (i.e. linear) and consist of a leaf sheath, which partially encloses the stem, and a spreading leaf blade. The leaf sheaths (4-12 cm long) are slightly hairy (i.e. sparsely pilose) or hairless (i.e. glabrous) and the lower ones become somewhat papery with age. The leaf blades (6-40 cm long and 1-5 mm wide) may be either flat or somewhat rolled (i.e. weakly convolute). They are hairless (i.e. glabrous) and have pointed tips (i.e. acuminate apices). Where the leaf sheathmeets the leaf blade there is a fringe of tiny hairs (i.e. ciliated ligule) or a tiny membrane (0.1-0.3 mm long) topped with hairs (i.e. ciliated membrane)

The dark green, dark grey or greyish-green coloured seed-heads, which are borne at the top of the flowering stems (i.e. culms), are very thin and elongated in appearance (6-35 cm long and 3-8 mm wide). They are upright (i.e. erect), spike-like (i.e. spiciformpanicles), and have many short branches (10-20 mm long) that are held very closely (i.e. appressed) to the main stem of the seed-head. These branches are quite densely arranged along the stem and are only sometimes interrupted near the base of theseed-head. Each of these seed-head branches bears numerous tiny, densely packed, flower spikelets almost to its base. The elongated (i.e. lanceolate) or egg-shaped (i.e.ovate) flower spikelets (2-2.8 mm long and 0.6-0.8 mm wide) contain a single tiny flower (i.e. floret) inside two bracts (i.e. glumes). The lower bract (i.e. glume) is 0.4-0.7 mm long and the upper bract (i.e. glume) is 1-1.5 mm long (i.e. at least half the length of the flower spikelet). Flowering occurs throughout the year, but is most abundant from spring through to late autumn (i.e. from October to June).

The oblong, oval-shaped (i.e. ellipsoid), or almost rounded (i.e. sub-globular) 'seeds' (i.e. grains or caryopses) turn dark red or reddish-brown in colour as they mature. They are tiny (1.1-1.5 mm long and up to 0.6 mm wide) and separate from the remainder of the flower spikelet at maturity (i.e. the whitish-coloured old glumes remain on the seed-head).

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