Description: Perennials or annuals, tufted or creeping.
Ligule usually a rim of short hairs; blade rolled in bud, flat or convolute, margins often ciliate.
Inflorescence a spike-like panicle or open, the branches sometimes whorled. Spikelets pedicellate, glabrous, often dark-coloured, florets 1, bisexual; rachis disarticulating above the glumes. Glumes usually unequal, narrow, acuminate, 1-nerved. Lemma as long as or longer than the glumes, soft, 1–3-nerved, awnless; palea equal to or shorter than the lemma, 2-nerved, notched or minutely bilobed, sometimes splitting between nerves. Mature grain with a loose pericarp that becomes sticky when wet.
Distribution and occurrence: World: c. 150 species, Africa, Asia, Malesia, Pacific islands. Australia: c. 19 species (c. 17 species native, 2 species naturalized), all States.
Derivation: from the Greek words for 'seed' and 'throwing', referring to the shedding of the seed from lemma, palea and pericarp. Some species are useful in pasture, others have become weeds.
Text by Jacobs, S.W.L., Whalley, R.D.B. & Wheeler, D.J.B. Taxon concept: Grasses of New South Wales, Fourth Edition (2008).
Taxa not yet included in identification key
Sporobolus coromandelianus,
Sporobolus pulchellus
| Key to the species | |
1 | Lowest node of inflorescence with branches (usually 3–several) in a whorl | 2 |
| Lowest node of inflorescence with only 1 or 2 branches (not whorled) | 4 |
2 | Panicle much branched and open; spikelets all distinctly pedicellate, pedicels and branches spreading | Sporobolus caroli |
| Panicle appearing to have fewer branches as both spikelets and branches are appressed to the axis; spikelets, many of which are sessile or subsessile, borne in small false spikes (spicate branches) Back to 1 | 3 |
3 | Panicle at least twice as long as the lowermost branches; each branch with a single, dense false spike, lower 30–50% naked; upper glume distinctly shorter than the spikelet | Sporobolus actinocladus |
| Panicle up to about twice as long as the lowermost branches; branches with several false spikes; upper glume about as long as the spikelet Back to 2 | Sporobolus contiguus |
4 | Upper glumes subequal or equal to the spikelet; inflorescence dense and spike-like; stoloniferous and/or rhizomatous perennials | 5 |
| Upper glume 25–75% the length of the spikelet; inflorescence open or spike-like; plants usually tufted Back to 1 | 6 |
5 | Creeping inland plants with stolons but not rhizomes; glabrous, with geniculate culms and leaf sheaths shorter than the internodes; blades alternate and distant; glumes usually shorter than the spikelet; spikelets 1.5–2 mm long | Sporobolus mitchellii |
| Rhizomatous and stoloniferous coastal perennials; leaves often hairy with sheaths exceeding the internodes of non-flowering culms; leaf blade tending to be arranged in pairs; glumes slightly shorter than to subequal to spikelet; spikelets 2–4 mm long Back to 4 | Sporobolus virginicus |
6 | Panicle always narrow continuous or interrupted; branches remaining close to the axis | 7 |
| Panicle branches spreading and diverging from the axis at maturity (panicle may be narrow before flowering) Back to 4 | 12 |
7 | Inflorescence very dense; if interrupted, primary axis only visible in lowest 30%; spikelets 2–2.5 mm long | 8 |
| Inflorescence not as dense; interrupted for most of its length (axis visible); spikelets 2 mm long or less Back to 6 | 11 |
8 | Inflorescence branches grouped in clusters | Sporobolus disjunctus |
| Inflorescence branches mostly solitary, never grouped in clusters Back to 7 | 9 |
9 | Mature grain held in the spikelet before exsertion such that it appears to be almost as long (80–90%) as the lemma; lower glume c. 75% the length of the upper glume (not recorded from N.S.W.) | Sporobolus indicus |
| Mature grain held in the spikelet before exsertion such that it appears to be slightly >50% as long as the lemma; lower glume to 50% the length of the upper glume Back to 8 | 10 |
10 | Spikelets 2–2.5 mm long; inflorescence branches usually remaining appressed | Sporobolus africanus |
| Spikelets 1.6–2 mm long; at least lower inflorescence branches often divergent at maturity Back to 9 | Sporobolus fertilis |
11 | Panicle with short, stiff, appressed branches, axis visible for most of panicle length | Sporobolus creber |
| Panicle with longer branches that tend to diverge from the axis in the lower 50% of the panicle, but conceal most of the axis in the upper half of the inflorescence Back to 7 | Sporobolus elongatus |
12 | Inflorescence branches free of spikelets for some distance from the base | 13 |
| Inflorescence branches with spikelets distributed more or less evenly all along; stamens 2–3 Back to 6 | 14 |
13 | Stamens always 3; spikelets 2 mm long | Sporobolus laxus |
| Stamens 2 or rarely 3; spikelets 1.2–1.6 mm long Back to 12 | Sporobolus diander |
14 | Robust plants often >1.5 m tall; inflorescence branches stiff and spreading | 15 |
| Plants mostly <1 m tall; inflorescence branches either lax and spreading or closely appressed Back to 12 | 16 |
15 | Upper glume acute, 30–50% the length of the spikelet; leaf blades to 7 mm wide; palea 2-lobed; grain 0.8–1 mm long | Sporobolus pyramidalis |
| Upper glume usually >50% spikelet length; leaf blades to 4 mm wide; palea entire; grain 0.7–0.8 mm long Back to 14 | Sporobolus natalensis |
16 | Spikelets 1.5–1.8 mm long; anthers 3; inflorescence usually contracted | Sporobolus blakei |
| Spikelets to 2 mm long; anthers usually 2; inflorescence usually open Back to 14 | Sporobolus sessilis |
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