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Poaceae Group 7
See list of 19 genera in this group-
1a. Inflorescence a solitary, terminal spike; spikelets arising from shallow cavities on the rachis, with a single, minute glume
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1b. Inflorescence a panicle or raceme (i.e., the spikelets at least shortly pedicellate), usually branched (though the branches sometimes difficult to discern); spikelets not arising from cavities on the rachis, with 2 glumes (glumes essentially absent in Leersia)
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2a. Inflorescence a dense, cylindrical, spike-like panicle, the branches virtually absent
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3a. Inflorescence overtopped by the upper leaves, usually partly sheathed or included in the subtending, apically inflated leaf sheath
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3b. Inflorescence exceeding the leaves, usually well exserted and not included in the upper leaf sheaths
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4a. Glumes without awns, connate at the base; paleas wanting
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4b. Glumes with awns, distinct at the base; paleas present, subequal in length to the lemmas
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5a. Glumes shorter than and not concealing the floret, the first glume with 2 (–3) awns, the second with a single awn (in part)
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5b. Glumes exceeding the length of the floret and concealing it [Fig. 251], glumes awnless or each glume with a single awn
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6a. Glumes tapering to a long point, but not awned, slightly swollen at the base; lemmas pubescent
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6b. Glumes awned [Fig. 251], not swollen at the base; lemmas glabrous over the surface
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7a. Awn of glumes 3–8 mm long; lemmas with awns; glumes hispidulous, bilobed at the apex, the awn emerging from between the lobes (in part)
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7b. Awn of glumes 0.7–3 mm long; lemmas without awns; glumes prominently ciliate on the keels [Fig. 251], otherwise glabrous, entire at the apex, the awn terminal
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2b. Inflorescence an open or dense panicle, the branches identifiable
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8a. Lemmas indurate and lustrous at maturity, of much firmer texture than the glumes
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9a. Lemmas awnless; spikelets with 1 fertile floret and at its base 2 sterile, rudimentary florets represented by pubescent scales
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9b. Lemmas with awns; spikelets without basal, sterile florets
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10b. Lemmas pubescent over the abaxial surface, with a single awn articulated and eventually deciduous from the summit of the lemma [Fig. 254]; callus of lemmas short and oblique; plants perennial
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11a. Panicle open to somewhat congested, the branches spreading to ascending, each branch bearing usually 2 or more spikelets; uppermost leaf blades well-developed, 1–35 cm long; basal leaves deciduous (in part)
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11b. Panicle very narrow, raceme-like, with appressed branches, each branch bearing usually a single spikelet; uppermost leaf blades absent or with a blade shorter than 1 cm; basal leaves evergreen (in part)
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8b. Lemmas soft and dull at maturity, not of conspicuously firmer texture than the glumes
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12a. Glumes virtually obsolete, reduced to minute cupules; nodes densely and conspicuously pubescent with spreading, white hairs [Fig. 237]
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12b. Glumes present and evident; nodes glabrous or pubescent, but not pubescent with spreading, white hairs
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13a. Floret stipitate, with 1 stamen; spikelets articulated below the glumes and falling intact leaving the pedicel behind
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13b. Floret sessile, with mostly 3 stamens; spikelets articulated above the glumes, the florets falling and leaving the empty glumes behind (disarticulating below the glumes in Polypogon)
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14a. Spikelets 10–15 mm long; plants growing on sandy beaches of the Atlantic coast and Lake Champlain
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14b. Spikelets 1–9 (–10) mm long; plants growing in a wide variety of habitats, but not regularly of coastal sands
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15a. Ligule of hairs; lemmas 1-veined (in part)
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15b. Ligule a membrane; lemmas 3- or 5-veined (the veins sometimes faint)
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16a. Glumes shorter than the lemmas or the lemmas awned from the very apex or both; caryopsis tightly enclosed by the lemma (in part)
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16b. At least 1 of the glumes equaling the length of the floret; awn of the lemma, if present, originating from below the apex on the keel of the lemma or from between 2 terminal lobes; caryopsis loosely enclosed by the lemma
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17a. Glumes obtuse; inflorescence a raceme with usually 6–8 spikelets; delicate annuals 3–10 cm tall
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17b. Glumes acute to acuminate; inflorescence a panicle, with more than 8 spikelets; annual or mostly perennial plants (5–) 10–200 cm tall
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18a. Lemma glabrous on the callus (pubescent in Agrostis elliottiana); palea nerveless, or, less often, 2-nerved, delicate, up to 65% as long as the lemma; rachilla not prolonged
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19a. Spikelets disarticulating above the glumes, borne on pedicels (0.1–) 0.3–9.6 mm long; lemmas (0.8–) 1.2–2.6 mm long
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19b. Spikelets disarticulating below the glumes, borne on stipes 0.1–0.6 mm long; lemmas 0.5–1.5 mm long (in part)
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18b. Lemma evidently, though sometimes shortly, pubescent on the callus [Figs. 202,203]; palea 2-nerved, membranaceous, ½ to fully as long as the lemma; rachilla prolonged beyond the upper floret as a minute bristle
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20a. Awn straight, inserted just below the apex and between the terminal teeth of the lemma, 5–12 mm long; pubescence of the callus of the lemma ca. ⅕ as long as the lemma; plants annual
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20b. Awn often bent, definitely originating from below the apex of the lemma, up to 3 mm long; pubescence of the callus of the lemma ¼ to fully as long as the lemma; plants perennial
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Each photo represents one genus in this subgroup.