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Poaceae Group 4
See list of 26 genera in this group-
1a. Leaf blades narrowed to a short pseudopetiole
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2a. Branches from midpoint of stem solitary; reproductive stems terete; spikelets pedicellate
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2b. Branches from midpoint of stem in pairs, strongly unequal; reproductive stems grooved on one side; spikelets sessile
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1b. Leaf blades not narrowed to a petiole-like structure
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3a. Plants robust, typically 1.5–4 m tall, forming extensive colonies by stout rhizomes; inflorescence appearing plumose due to long-pubescent rachilla segments
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3b. Plants of short to moderate stature, mostly shorter than 2 m, colonial or not; inflorescence not appearing plumose
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4a. Lemmas with 3 veins
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5a. Callus and/or nerves of the lemma pubescent
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6b. Lemmas bifid at the apex, with an awn emerging from between the lobes (note, the lateral lobes may terminate in long awns), pubescent, but not with arachnoid hairs; ligule a band of hairs
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7a. Lemmas with 3 slender, elongate awns—1 terminal awn and 2 lateral awns; upper glume bifid at the apex
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7b. Lemmas with 1 slender awn or 3 excurrent mucros; upper glume entire at the apex
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8a. Inflorescence terminal, long-exserted from upper leaf sheaths; paleas glabrous or inconspicuously short-pubescent; lateral veins of lemma shortly excurrent as short awns
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8b. Inflorescence terminal and axillary, usually partly included in the leaf sheaths; paleas densely villous on the apical portion of the 2 keels; lateral veins of lemma not excurrent
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5b. Callus and nerves of the lemma glabrous
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9a. Lemmas keeled on the abaxial surface (except E. intermedia), longer than the paleas; anthers 0.2–1.2 mm long; rachilla typically not disarticulating, the floral scales falling from it
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9b. Lemmas rounded on the abaxial surface, shorter than the paleas; anthers 1.5–3 mm long; rachilla disarticulating
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4b. Lemmas with 5 or more veins (the intermediate veins sometimes inconspicuous)
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10a. Panicle composed of dense, somewhat secund, glomerules of spikelets on a few, stiff branches
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10b. Panicle composed of pedicellate spikelets on spirally arranged branches
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11a. Plants dioecious (i.e., the flowers of a given plant unisexual and all of one type), of coastal saltmarshes
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11b. Plants synoecious (i.e., the flowers of a given plant bisexual), mostly not of saline habitats (except Puccinellia)
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12a. Leaf sheath fused (i.e., the sheath closed with united edges) at least in the basal half
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13a. Lemmas entire at the apex, without awns, with parallel veins that do not converge near the apex [Fig. 265]
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13b. Lemmas bifid at the apex, awned in most species [Fig. 196], with arching veins that converge near the apex
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14a. Callus of the lemma pubescent; styles borne close together from the summit of the ovary; caryopsis free from the palea
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14b. Callus of the lemma glabrous; styles separated and borne below the summit of the ovary; caryopsis adnate to the palea
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12b. Leaf sheath with distinct, overlapping edges except at the very base
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15b. Glumes relatively similar in shape, though sometimes differing in size, both with parallel or apically tapering margins [Figs. 208,281]
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16a. Lemmas awned, the awn attached to the abaxial surface of the lemma well below the apex [Fig. 208]
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17a. Spikelets 9–10 mm long; awn of upper lemmas of spikelet 10–16 mm long; upper glume 3- to 9-veined (in part)
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17b. Spikelets 2.3–7.5 mm long; awn of lemmas up to 6.5 mm long; upper glume 1- to 3-veined
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18a. Awn emerging below the middle of the lemma keel; lemma apex entire (in part)
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18b. Awn emerging above the middle of the lemma keel; lemma apex bifid (in part)
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16b. Lemmas unawned or with an awn attached at the apex [Fig. 265]
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19a. Florets nearly perpendicular to the axis of spikelet; lemmas cordate at their base
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19b. Florets ascending to erect relative to the spikelet axis; lemmas cuneate to rounded or truncate at their base
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20a. Lemmas usually blunt at the apex, with parallel veins that do not converge near the tip [Figs. 264,265]
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21a. Lemmas prominently veined; plants of freshwater habitats
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21b. Lemmas inconspicuously veined; plants of saline habitats (e.g., saline to brackish marshes, coastal strands, heavily salted roadways)
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20b. Lemmas usually pointed or awned or both at the apex, with arching veins that converge near the tip
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22a. Rachilla segments with hairs 1.3–2 mm long; callus of lemma pubescent with straight hairs (in part)
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22b. Rachilla segments glabrous or minutely scabrous; callus of lemma glabrous or with arachnoid hairs
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23a. Lemmas prominently keeled, often with arachnoid pubescence on the callus [Fig. 261], without awns; leaf tips cucullate (in part)
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23b. Lemmas rounded, or keeled only at the apex, with a glabrous callus, usually awned; leaf tips flat
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24a. Panicles with short, ± secund branches; lemmas obtuse at the apex, unawned; florets disarticulating with a short rachilla segment such that the fallen florets appear stipitate
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24b. Panicles with short to long branches, not secund; lemmas acute to acuminate (obtuse), awned in most species [Fig. 283]; florets disarticulating without a short rachilla segment or with 1 but then the floret not appearing stipitate
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25a. Plants annual; flowers remaining closed (i.e., cleistogamous; anthers usually 1 per floret, up to 1 mm long
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25b. Plants perennial; flowers open-pollinated (i.e., chasmogamous) or proliferating in one species; anthers 3 per floret, (0.5–) 0.7–4 mm long
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26a. Auricles present at summit of leaf sheath [Fig. 266]; apical half of the lemma with a prominent, scarious margin ca. 0.5 mm wide; leaf blades flat, (2–) 3–18 mm wide
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26b. Auricles absent; lemmas with firm margins or very narrow, inconspicuous, scarious margins; leaf blades involute, conduplicate, or flat, 0.2–3 mm wide or up to 10 mm in F. subverticillata
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Each photo represents one genus in this subgroup.