Flora of the Southeastern United States
2022 Edition

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Key to Poaceae, Key N: grasses with 2+ florets, these readily visible by extending past the glumes

1 Plants dioecious; plants strongly rhizomatous-clonal; [plants of saline situations, coastal or more rarely inland]; [tribe Cynodonteae; subtribe Monanthochloinae]
1 Plants bisexual; plants cespitose or weakly short- rhizomatous; [plants of various habitats, including saline].
..2 Lemmas 1-3-nerved, the nerves strong and obvious; spikelets 1-27 mm long.
....3 Lemma nerves hairy; lemmas slightly to strongly 2-lobed, the midnerve shortly excurrent between the 2 lobes; [tribe Cynodonteae; subtribe Tridentinae].
......4 Palea glabrous or with hairs < 0.5 mm long; plants perennial; inflorescences exserted, conspicuous
......4 Palea long-ciliate on the upper half, the hairs 0.5-2 mm long; plants annual; inflorescences often largely hidden in the upper sheath
....3 Lemma nerves glabrous; lemmas not at all lobed.
........5 Mature spikelets stiff; grains protruding, with a bottle-neck-like beak; [tribe Diarrheneae]
........5 Mature spikelets not stiff; grains neither protruding, nor shaped with a bottleneck-like beak.
..........6 Florets 3-34 per spikelet; lemmas unawned; [tribe Eragrostideae; subtribe Eragrostidinae]
..........6 Florets 2-3 per spikelet; lemmas awned or unawned; [tribe Poeae]
..2 Lemmas 5-many-nerved, the nerves often obscure; spikelets 2-70 mm long.
............ 7 Sheaths united for at least ½ their length.
............ ..8 Spikelets in dense one-sided clusters on a few stiff branches; spikelets strongly flattened; [tribe Poeae]
............ ..8 Spikelets in open or somewhat congested panicles, not as above; spikelets slightly to not at all flattened.
............ ....9 Lemmas awned.
............ ......10 Callus of the lemma glabrous; [collectively widespread]; [tribe Bromeae]
............ ......10 Callus of the lemma pubescent; [of VA, WV, KY, and northward]; [tribe Meliceae]
............ ....9 Lemmas unawned.
............ ........11 Lower glumes 1-veined; [plants of wetlands]
............ ........11 Lower glumes 3-7-veined; [plants of mesic to dry habitats]
............ 7 Sheaths completely free or united at most up to ½ their length.
............ ..........12 Basal 1-8 florets of the spikelet sterile.
............ ............ 13 Ligule membranous (the membrane apex ciliate); lower 1-4 florets sterile; disarticulation above the glumes and between the florets; [of various, usually moist, habitats, collectively widespread]; [tribe Centotheceae]
............ ............ 13 Ligule of hairs; lower 2-8 florets sterile; disarticulation below the glumes (the spikelet falling whole); [of coastal dunes, from se. VA southward and westward]; [tribe Eragrostideae; subtribe Uniolinae]
............ ..........12 Lowermost florets of the spikelet fertile; [tribe Poeae].
............ ............ ..14 Lemmas about as broad as long, spreading at a ca. 90° angle to the rachilla
............ ............ ..14 Lemmas longer than broad, ascending at an acute angle to the rachilla.
............ ............ ....15 Lemmas rounded at the apex, not awned.
............ ............ ......16 Lemmas obscurely (3-) 5 (-7) nerved; spikelets 2.5-13 mm long
............ ............ ......16 Lemmas prominently 5-9-nerved; spikelets 3.6-6.5 mm long
............ ............ ....15 Lemmas acute at the apex, or awned.
............ ............ ........17 Callus of the lemmas hairy
 Poa
............ ............ ........17 Callus of the lemma glabrous.
............ ............ ..........18 Lemmas awned.
............ ............ ............ 19 Plant annual; stamen 1
............ ............ ............ 19 Plant perennial; stamens 3.
............ ............ ............ ..20 Leaf blades often involute, 0.2-3 mm wide, not auriculate at the base
............ ............ ............ ..20 Leaf blades flat, 3-12 mm wide, auriculate at the base
............ ............ ..........18 Lemmas unawned.
............ ............ ............ ....21 Leaf tips blunt, cupped like the prow of a row-boat
 Poa
............ ............ ............ ....21 Leaf tips acuminate, planar or keeled (but not as above).
............ ............ ............ ......22 Leaf blades often involute, 0.2-3 mm wide, or flat and 3-12 mm wide, not auriculate at the base
............ ............ ............ ......22 Leaf blades flat, 3-12 mm wide, auriculate at the base