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1 Spikelets 2-flowered, often dorsally compressed, falling entire at maturity (the abscission below the glumes), the upper floret usually bisexual, the lower one male or sterile; [tribe Paniceae] |
..2 Lemma margins hyaline, flat; lower glumes various (absent, < ¼ the length, or longer than the upper glume) |
..2 Lemma margins not hyaline, frequently involute; lower glumes absent or < ¼ the length of the upper glume. |
....3 Spikelets with lower lemmas (and lower glumes, if present) adjacent to the branch axes. |
......4 Lower glumes absent |
......4 Lower glumes present on at least most spikelets |
....3 Spikelets with upper lemmas (and upper glumes, if present) adjacent or appressed to the branch axes. |
........5 Both glumes absent from all or most spikelets |
........5 Upper or both glumes present on all spikelets. |
..........6 Lower glumes usually absent; upper lemmas smooth to slightly rugose |
..........6 Lower glumes present; upper lemmas rugose and verrucose |
1 Spikelets 1-, 2-, or many-flowered, usually terete or somewhat laterally compressed, either abscising at maturing above the glumes or if 2-flowered then both florets bisexual, or the upper sterile; [tribes Cynodonteae and Zoysieae] |
............ 7 Spikes normally solitary (rarely 2), divergent at the summit of the culm; second glume with a recurved spine arising from the back; fresh plants aromatic with a citrus odor; [tribe Cynodonteae; subtribe “incertae sedis”] |
............ 7 Spikes normally 2 or more, alternate, digitate, subdigitate, or verticillate along the main inflorescence axis; second glume lacking a recurved spine; fresh plants not aromatic with a citrus odor. |
............ ..8 Spikes arranged along the central inflorescence axis alternately, solitary at each node. |
............ ....9 Spikelets with 1 bisexual floret, sometimes also with modified male, sterile, or rudimentary florets above the fertile floret. |
............ ......10 Spikelets with modified male, sterile, or rudimentary florets above the fertile floret; [plants of uplands]; [tribe Cynodonteae; subtribe Boutelouinae] |
............ ......10 Spikelets lacking any modified florets; [plants of wetlands, primarily saline and coastal]; [tribe Zoysieae; subtribe Sporobolinae] |
............ ....9 Spikelets with 2 or more bisexual florets (sometimes also with additional reduced florets); [tribe Cynodonteae; subtribe Eleusininae]. |
............ ........11 Ligules 4-8 (-15) mm long, acute to attenuate, entire (lacerate only by tearing) |
............ ........11 Ligules 0.3-5.4 mm long, truncate to obtuse, erose or entire. |
............ ..........12 Lemmas 3-veined; ligule (0.2-) 0.5-5.5 (-7.0) mm long; apex erose or entire |
............ ..........12 Lemmas 5-veined; ligule 0.8-2.2 mm long, apex erose |
............ ..8 Spikes arranged along the central inflorescence axis in a digitate, subdigitate, or verticillate manner, all or most nodes with 2 or more spikes; [tribe Cynodonteae]. |
............ ............ 13 Spikelets with 1 fertile floret (there may also be 1 or more sterile florets); [tribe Cynodonteae; subtribe Eleusininae]. |
............ ............ ..14 Spikelets lacking sterile florets |
............ ............ ..14 Spikelets with 1 or more sterile florets. |
............ ............ ....15 Lowest lemmas awned (rarely unawned); upper glumes acute to acuminate, mucronate or short-awned |
............ ............ ....15 Lowest lemmas unawned (or with an awn to 1.2 mm long); upper glumes truncate or bilobed, sometimes short-awned from between the lobes |
............ ............ 13 Spikelets with 2 or more fertile florets. |
............ ............ ......16 Spikes to 7 cm long, terminating in a point (the spikes acuminate); [tribe Cynodonteae; subtribe “incertae sedis”] |
............ ............ ......16 Spikes to 22 cm long, terminating in a functional or rudimentary spikelet (the spikes acute to obtuse); [tribe Cynodonteae; subtribe Eleusininae]. |
............ ............ ........17 Lemmas glabrous |
............ ............ ........17 Lemmas pubescent, at least towards the base. |
............ ............ ..........18 Lemma apices obtuse to truncate or emarginate |
............ ............ ..........18 Lemma apices acute |