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1 Inflorescence an array of spikes, the spikelets closely imbricate in 2 rows along the rachis of the spikes, the spikes alternate along the primary inflorescence axis; [tribe Zoysieae; subtribe Sporobolinae] |
1 Inflorescence otherwise, either the spikelets embedded or in grooves in an thickened rachis, or the inflorescence a slender or broad panicle. |
..2 Spikelets embedded in the thickened rachis (the inflorescence thus like an ear of corn), or fitting into grooves in the thickened rachis (the inflorescence thus cylindrical and resembling a rat's tail). Spikelets unisexual, with male and female spikelets in separate inflorescences or in different parts of the same inflorescence; [tribe Andropogoneae]. |
....3 Racemes of mixed sex (female below, male above) |
....3 Racemes of single sex |
..2 Spikelets not embedded or fitting into grooves in the rachis, the inflorescence a slender or broad panicle (the spikelets visibly separate and often pedicelled). |
......4 Spikelets with a single floret, this unisexual (either pistillate or staminate); plants with aerenchymatous culms, [plants of seasonally or tidally flooded wetlands]; [tribe Oryzeae]. |
........5 Pistillate spikelets on the upper branches of the panicle, staminate spikelets on the lower branches; lemmas and paleas clasping along their margins; plants annual |
........5 Pistillate and staminate spikelets intermingled on the same branches of the inflorescence; lemma margins free; plants perennial |
......4 Spikelets with 2 or more florets, at least some of these bisexual; plants without aerenchymatous culms, [plants of uplands or temporarily to seasonally flooded wetlands]. |
..........6 Spikelets with 2-8 florets, these bisexual. |
............ 7 Leaves primarily basal, plants densely cespitose. |
............ ..8 ; [tribe Arundineae |
............ ..8 Panicles plumose; [tribe Danthonieae] |
............ 7 Leaves cauline; plants short-rhizomatous (somewhat clumped) to long-rhizomatous; [tribe Arundineae]. |
............ ....9 Lemmas pilose; rachilla glabrous; plants short-rhizomatous (somewhat clumped); culms to 10 m tall; [plants of uplands or saturated or temporarily flooded wetlands] |
............ ....9 Lemmas glabrous; rachilla sericeous; plants long rhizomatous; culms to 4 m tall; [plants of uplands or saturated, tidally flooded, or seasonally flooded wetlands] |
..........6 Spikelets almost always with 2 florets, the lower florets sterile or staminate (sometimes reduced to lemmas or completely absent). |
............ ......10 Spikelets falling separately, not attached to rachis segments, stalks, or bristles; spikelets <2× as long as wide; [tribe Paniceae]. |
............ ........11 Spikelets (at least the terminal) subtended by 1-many stiff, terete bristles |
............ ........11 Spikelets not subtended by stiff bristles. |
............ ..........12 Fertile lemma rugose with cross-venation |
............ ..........12 Fertile lemma smooth or hairy, not rugose |
............ ......10 Spikelets falling with attached rachis segments, stalks, or bristles; spikelets >3× as long as wide; [tribe Andropogoneae]. |
............ ............ 13 Pedicelled spikelet differing from the sessile in shape and sex (sometimes represented only by a pedicel). |
............ ............ ..14 Inflorescence of 2-13 digitate (whorled) racemes borne at the summit of a peduncle, the peduncle subtended by a raceme sheath |
............ ............ ..14 Inflorescence a panicle, the branches not subtended by sheaths. |
............ ............ ....15 Pedicelled spikelet represented by pedicel only; apex of sheath bearing 2 auricles 1-10 mm long; [native] |
............ ............ ....15 Pedicelled spikelet present, staminate; apex of sheath truncate; [exotic] |
............ ............ 13 Pedicelled spikelet similar to the sessile spikelet, both fertile. |
............ ............ ......16 Spikelets falling separately from the persistent rachis |
............ ............ ......16 Spikelets falling in pairs together with sections of the disarticulating rachis |
............ ............ ........17 Spikelets awned with awns 10-26 mm long; anthers 2; [native, collectively common and widespread] |
............ ............ ........17 Spikelets unawned or with awns to 5.2 mm long; anthers 3; [exotic, rarely encountered] |
............ ............ ..........18 Spikelets unawned |
............ ............ ..........18 Spikelets with awns 4-5.2 mm long |