| 1 |
Plants dioecious; female inflorescence a large globose spiny head. |
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179 Spinifex |
| + |
Plants bisexual; inflorescence not as above |
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(2) |
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| 2 (1) |
Spikelets of 2 kinds, the upper staminate portion of the raceme folding over 1–2 bisexual spikelets. |
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168 Thuarea |
| + |
Spikelets all alike |
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(3) |
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| 3 (2) |
Spikelets (at least some of them) subtended by bristles or a spiny involucre; or raceme rachis prolonged into a bristle or short point beyond the uppermost spikelet |
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(4) |
| + |
Spikelets not subtended by bristles; or raceme rachis terminating in a spikelet |
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(9) |
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| 4 (3) |
Inflorescence of racemes, only the uppermost spikelet of each raceme subtended by a bristle or short (often inconspicuous) point |
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(5) |
| + |
Inflorescence paniculate, often spikelike, all or many of the spikelets subtended by bristles or a spiny involucre |
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(7) |
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| 5 (4) |
Racemes ending in a long bristle; upper glume acuminate-aristate. |
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176 Pseudoraphis |
| + |
Racemes ending in an inconspicuous point; upper glume not awned |
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(6) |
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| 6 (5) |
Racemes very short, sunk in pockets on the broad or thick inflorescence axis; upper lemma smooth. |
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173 Stenotaphrum |
| + |
Racemes not sunk in pockets, inflorescence axis slender; upper lemma rugose or granulate. |
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172 Paspalidium |
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| 7 (4) |
Bristles persisting on the axis after the spikelets have fallen. |
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171 Setaria |
| + |
Bristles or spines falling as involucres around the spikelets |
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(8) |
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| 8 (7) |
Involucral bristles slender, free to the base. |
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177 Pennisetum |
| + |
Involucral bristles and spines flattened and connate below, forming a cup. |
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178 Cenchrus |
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| 9 (3) |
Inflorescence an open, contracted or spikelike panicle; pedicels usually all slender and distinct |
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(10) |
| + |
Inflorescence of unilateral racemes; spikelets usually single or paired; pedicels often very short, at least for one spikelet of a pair |
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(18) |
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| 10 (9) |
Spikelets laterally compressed |
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(11) |
| + |
Spikelets dorsally compressed |
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(13) |
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| 11 (10) |
Glumes keeled; upper floret with wings or scars at the base. |
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155 Ichnanthus |
| + |
Glumes not keeled; upper floret without basal wings or scars |
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(12) |
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| 12 (11) |
Lower lemma entire, awnless; upper lemma gibbously semiorbicular with a little greenish crest near the apex. |
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160 Cyrtococcum |
| + |
Lower lemma bilobed or shortly awned; upper lemma elliptic, not crested. |
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174 Melinis |
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| 13 (10) |
Panicle spikelike |
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(14) |
| + |
Panicle open, the spikelets evenly spaced or appressed along the primary branches |
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(15) |
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| 14 (13) |
Upper glume gibbous; culms hollow. |
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158 Sacciolepis |
| + |
Upper glume not gibbous; culms filled with aerenchyma. |
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157 Hymenachne |
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| 15 (13) |
Upper glume as long as or only slightly shorter than the spikelet |
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(16) |
| + |
Upper glume 2/3 spikelet length or less |
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(17) |
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| 16 (15) |
Margins of upper palea free toward apex; trailing semi-aquatic perennial |
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157 Hymenachne |
| + |
Margins of upper palea clasped by upper lemma along whole length. |
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156 Panicum |
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| 17 (15) |
Upper glume 1/2–2/3 spikelet length, 3–5-veined; spikelets on short appressed secondary racemelets |
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159 Ottochloa |
| + |
Upper glume very small, usually veinless; spikelets on long capillary pedicels |
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175 Digitaria |
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| 18 (9) |
Apex of upper lemma awned, crested or with a tuft of setae |
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(19) |
| + |
Apex of upper lemma not as above |
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(21) |
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| 19 (18) |
Upper lemma awned; upper glume ciliate on the margins. |
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164 Alloteropsis |
| + |
Upper lemma apex crested or with a tuft of setae; upper glume glabrous |
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(20) |
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| 20 (19) |
Apex of upper lemma with a tuft of short setae. |
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161 Setiacis |
| + |
Apex of upper lemma with a little green crest. |
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162 Acroceras |
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| 21 (18) |
Spikelets laterally compressed or glumes awned; leaf blades lanceolate to ovate; trailing forest grasses |
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(22) |
| + |
Spikelets dorsally compressed; lower glume awnless |
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(23) |
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| 22 (21) |
Glumes not awned, upper glume armed with hooked bristles at maturity. |
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153 Pseudechinolaena |
| + |
Glumes awned, the awns often sticky. |
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154 Oplismenus |
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| 23 (21) |
Spikelets densely packed in 4 rows or congested into clusters; apex of upper palea reflexed |
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163 Echinochloa |
| + |
Spikelets mostly in 1 or 2 rows; apex of upper palea tucked in |
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(24) |
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| 24 (23) |
Spikelets supported on a basal globular beadlike swelling; lower glume vestigial. |
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167 Eriochloa |
| + |
Spikelets without a basal beadlike swelling (rarely with a barrel-shaped basal stipe, but then lower glume well developed) |
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(25) |
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| 25 (24) |
Upper lemma cartilaginous to papery, the margins broad, flat and hyaline, covering much of the palea |
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175 Digitaria |
| + |
Upper lemma coriaceous to bony with inrolled or flat margins exposing much of the palea (if texture thinner then margins inrolled) |
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(26) |
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| 26 (25) |
Lower glume present |
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(27) |
| + |
Lower glume absent |
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(28) |
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| 27 (26) |
Upper lemma acute, obtuse or briefly mucronulate, subequaling spikelet; spikelets plumply elliptic, acute or obtuse; back of upper lemma facing away from rachis. |
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165 Brachiaria |
| + |
Upper glume clearly mucronate, shorter than spikelet; spikelets plano-convex, acuminate; back of upper lemma lying against rachis. |
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166 Urochloa |
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| 28 (26) |
Back of upper lemma lying against rachis; spikelets strongly plano-convex, often orbicular. |
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169 Paspalum |
| + |
Back of upper lemma facing away from rachis; spikelets thinly biconvex, oblong-elliptic. |
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170 Axonopus |
