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.
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.
| | 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 |
