Description: Tufted or stoloniferous annuals or perennials.
Ligule a ciliate membranous rim or fringe of short hairs; blade rolled in bud, flat, hairy.
Inflorescence a primary axis of variable length, often hairy, with few to many spike-like racemes (sometimes with secondary branching) arranged along it, spikelets secund (arranged on one side) and often spreading at maturity. Spikelets plump or dorsally compressed, appearing shortly pedicellate, often hairy or subtended by hairs or bristles, falling entire at maturity; florets 2, the upper bisexual and the lower male or sterile. Glumes membranous, unequal; lower shorter and encircling the spikelet, the base sometimes prolonged into a stipe; upper glume equal or subequal to the lower lemma. Lower lemma membranous and often hairy; palea shorter than the lemma or absent. Fertile lemma often shorter than the lower, hardened, transversely rugose or rugulose, mucronate or awned or the lemma tip recurved over the palea; palea tightly enfolded by the lemma, the tip enclosed by the lemma.
Distribution and occurrence: World: c. 100 species, tropical regions. Australia: c. 28 species (c. 18 species native, 10 species naturalized), all mainland States except Vic.
Text by Jacobs, S.W.L., Whalley, R.D.B. & Wheeler, D.J.B.
Taxon concept: Grasses of New South Wales, Fourth Edition (2008).
| ||Key to the species|| |
|1||Upper lemma awned or mucronate, mucro usually c. 1 mm long||2|
|Upper lemma neither awned nor mucronate but may have a recurved tip||6|
|2||Lower glume less than 0.8 mm long, c. 15% the spikelet length; inflorescence branches with a narrow wing||3|
|Lower glume 1–3.3 mm long, 25% the spikelet length or more; inflorescence branches with narrow or wide wings|
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|3||Spikelets hairy||Urochloa gilesii|
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|4||Spikelets 3–4 mm long, arranged loosely on the branches; lower glume adaxial; mucro on upper lemma short||Urochloa praetervisa|
|Spikelets 4–5 mm long, evenly arranged on the branches and partly overlapping; lower glume abaxial; awn or mucro conspicuous|
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|5||Lower glume 1–1.5 mm long, c. 25% as long as the spikelet, glabrous; annual||Urochloa panicoides|
|Lower glume more than 50% spikelet length, often with a few long hairs; perennial|
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|6||Lower lemma with a palea||7|
|Lower lemma without a palea|
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|7||Spikelets 4–6 mm long, distinctly hairy||8|
|Spikelets less than 4 mm long, glabrous|
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|8||Strongly stoloniferous perennial; spikelets 4–6 mm long, not constricted in the lower part, arranged evenly on 1 side of the ribbon-like rachis; racemes 2 or 3||Urochloa decumbens|
|Plants not stoloniferous but may occasionally root at lower nodes, annuals or perennials; spikelets 5–6 mm long, basal part narrow and constricted; racemes to 10|
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|9||Lower floret male; spikelets crowded on the branches; pedicel apices with a ring of hairs; annual||Urochloa texana|
|Lower floret sterile; spikelets loosely arranged on the racemes; pedicel apices glabrous; perennial|
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|10||Stoloniferous perennial with flowering culms erect, to 2 m high; spikelets 3–3.5 mm long; lower floret male; racemes on an elongated axis to 30 cm long||Urochloa mutica|
|Tufted annual; culms less than 1 m high; spikelets 3 mm long; lower floret sterile; racemes on an axis less than 15 cm long|
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|11||Spikelets 3–3.5 mm long, very densely arranged on the branches; upper glume and lower lemma more or less uniformly pubescent||Urochloa advena|
|Spikelets 3.5–4.5 mm long, more loosely arranged on the branches; upper glume and lower lemma glabrous or with long hairs near the top|
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|12||Spikelets glabrous||Urochloa subquadripara|
|Spikelets with long hairs on upper part of upper glume and lower lemma|
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