Flora of the Southeastern United States
2022 Edition

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Key to Poaceae, Key H: finger grasses

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