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Poaceae Group 10
See list of 19 genera in this group-
1a. Plants monoecious, the carpellate and staminate inflorescences or portions of inflorescences clearly different from one another; glumes absent, highly reduced, or collapsed (i.e., not evident); robust, annual grasses 1–5 (–6) m tall
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2a. Each inflorescence with 2 types of flowers, the staminate positioned below the carpellate; carpellate spikelets with elongate awns; aquatic grasses
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2b. Each inflorescence with only 1 type of flower, the carpellate inflorescences axillary, the staminate inflorescences terminal; carpellate spikelets lacking awns; cultivated grasses
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1b. Plants synoecious or polygamous, the inflorescence with at least some (or entirely of) bisexual flowers; glumes present (though sometimes the lower one absent); short to tall, annual or perennial grasses 0.15–2.5 (–3) m tall
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3a. Lemmas without awns [Fig. 269]
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4a. Spikelets at maturity with 1 pair of lemmas and paleas indurate and lustrous, of much firmer texture than the glumes
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5b. Spikelets not subtended by bristles; inflorescence an open to dense panicle
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6a. Upper leaves (or all the leaves) without ligules (in part)
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6b. Leaves with ligules of hairs, membranes, or ciliate membranes
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8a. Spikelets lanceoloid to ellipsoid; upper (i.e., fertile) lemma somewhat indurate, firm but flexible, the margin with a hyaline border and flat (in part)
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8b. Spikelets ovoid or obovoid to spherical; upper lemma prominently indurate, rigid to the edges and lacking a hyaline border, the very edges slightly involute
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7b. Panicle branches rebranched (at least the lower ones) or not secund or usually both [Figs. 216,246,247]
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9a. Plants with both aerial and subterranean inflorescences, only the subterranean ones producing fruits; lower glumes absent
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9b. Plants with only aerial inflorescences, at least some spikelets producing fruits; lower glumes present, though sometimes very small
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10a. Upper (i.e., fertile) lemma somewhat indurate, firm but flexible, the margin with a hyaline border and flat (in part)
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10b. Upper lemma prominently indurate, rigid to the edges and lacking a hyaline border, the very edges slightly involute
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11a. Upper lemma transversely rugose; panicle branches spike-like, secund, with a triquetrous axis
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11b. Upper lemma not transversely rugose (verrucose in Panicum verrucosum, but the warts not aligned in rows); panicle branches open-branched to highly congested, not secund (+/- secund in Sorengia), without a triquetrous axis
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12a. Inflorescence dense, spike-like, concealing at least the apical ½ of the inflorescence rachis; pedicels with a disk-like apex; upper glume saccate at base
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12b. Inflorescence an open to somewhat congested panicle, the inflorescence rachis visible; pedicels not or barely thickened at apex, not disk-like; upper glume not saccate
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13a. Basal leaves lanceolate to ovate, of distinctly different shape and/or length than the stem leaves and forming an overwintering rosette (elongate and similar to stem leaves in 2 species); many species producing branches from the lower and middle stem nodes in summer, these sometimes rebranching; reduced secondary panicles produced bearing cleistogamous flowers and often partly concealed by subtending leaves; plants perennial
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13b. Basal leaves linear to lanceolate, similar to the stem leaves, not forming an overwintering rosette; many species not producing branches from the lower and middle nodes, or branches produced but not rebranched; secondary panicles similar to the terminal panicles, chasmogamous; plants annual or perennial
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14a. Spikelets borne on short pedicels mostly 0.5–1.5 mm long, ± secund [Fig. 271]; leaf sheaths strongly compressed; apex of lemma and palea of upper floret lacking papillae
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14b. Spikelets borne on pedicels (0.5–) 1–20 mm long, not secund; leaf sheaths ± terete or compressed in P. dichotomiflorum; apex of lemma and palea of upper floret with simple or compound papillae
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4b. Spikelets with soft to firm lemmas, the lemmas dull and not conspicuously indurate
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15a. Spikelet with an upper bisexual, fertile floret and a lower inconspicuous, sterile floret, articulated below the glumes, the entire spikelet falling and leaving the pedicel behind; upper glume and lower lemma usually of ± similar appearance and texture (in part)
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15b. Spikelet with 1 bisexual, fertile floret, articulated above the glumes, the floret falling leaving the empty glumes behind; upper glume and lemma not of similar appearance and texture
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16a. Lemmas 1-veined, unawned; ligule of hairs (in part)
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16b. Lemmas 3-veined, awned in most species; ligule a membrane (in part)
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17a. Upper leaves (or all the leaves) without ligules (in part)
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17b. Leaves with ligules of hairs, membranes, or ciliate membranes
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18a. Lemmas with 3 awns at the apex; plants annual (or perennial in 2 species) (in part)
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18b. Lemmas with a single awn from the apex; plants perennial
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19a. Lemmas indurate and lustrous, conspicuously firmer than the glumes, pilose over the abaxial surface (only in the basal ⅓ in Piptochaetium); awn of lemma articulated, persistent or eventually deciduous
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20a. Lemma awn 45–70 mm long; spikelets 9–13 mm long excluding the awns; lemmas with 3 distinct zones—villous in basal ⅓, glabrous in the middle, and scabrous near the apex [Fig. 255]
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20b. Lemma awn 0.5–14 mm long; spikelets 3.5–9 mm long excluding the awns; lemmas sparsely to densely pubescent ± throughout
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21a. Panicle open to somewhat congested, the branches spreading to ascending, each branch usually bearing 2 or more spikelets; uppermost leaf blades well-developed, 1–35 cm long; basal leaves deciduous (in part)
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21b. Panicle very narrow, raceme-like, with appressed branches, each branch usually bearing a single spikelet; uppermost leaf blades absent or with a blade shorter than 1 cm; basal leaves evergreen (in part)
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19b. Lemmas firm, but not indurate, dull, glabrous or scaberulous, pubescent only on the nerves or callus if at all (minutely pubescent between the nerves in some Muhlenbergia); awn of lemma not articulated, persistent
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22a. First glume diminutive or obsolete; rachilla prolonged, located near the abaxial surface of the palea and appearing as a minute bristle; plants with rhizomes
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22b. First glume present and evident (except in M. schreberi, which lacks rhizomes); rachilla not prolonged; plants with or without rhizomes (in part)
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Each photo represents one genus in this subgroup.