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POACEAE Tribe PANICEAE
Annual or perennial herbs. Leaf-blades usually flat and linear to lanceolate; ligule membranous or a row of hairs, rarely absent. Inflorescence an open, contracted or spike-like panicle, or composed of racemes arranged digitately or racemosely (very rarely spatheate), sometimes the spikelets subtended or surrounded by reduced bristle-like branches. Spikelets all alike, solitary or inconspicuously paired, mostly dorsally compressed, 2-flowered, falling entire at maturity, commonly. awnless; glumes membranous or herbaceous, the lower usually shorter than the upper and sometimes much reduced or absent; lower floret male or barren, the lemma similar to the upper glume; upper floret bisexual, the lemma and palea ± indurated, sometimes mucronate; lodicules usually 2; stamens 3; stigmas 2. Grain with large embryo and punctiform hilum; starch grains simple, angular. Chromosomes small, basic number 7, 9 or 10.
Genera ± 86; throughout the tropics, extending into warm temperate regions; 15 genera and 73 species in Pakistan.
A large well-defined tribe, recognised by the upper floret which is typically hard and shining like a little cowrie shell. Among racemose genera with solitary spikelets, the orientation of the spikelet is termed adaxial when the lower glume faces the rhachis, and abaxial when it is turned away; the orientation of paired spikelets is indeterminate. The extent to which the upper palea is covered by the lemma-margins refers to the flowering condition; the palea is usually more exposed when the floret is turgid with fruit. Three species reported from Sind are listed by Stewart (Ann. Cat. Vasc. Pl. W. Pak.) but their occurrence in Pakistan has not been confirmed. Spinifex littoreus (Burm.f.) Merr. and Stenotaphrum dimidiatum (Linn.) Brongn. are both largely confined to southern India, the former also in Burma and the latter also in East Africa, S0acciolepis interrupta (Wind.) Stapf is found in the tropics of Southeast Asia.
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| 1 |
Spikelets not subtended by bristles |
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(2) |
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Spikelets, or some of them, subtended by 1-many bristles or spines |
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(13) |
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| 2 (1) |
Inflorescence an open or spike-like panicle, occasionally condensed about the primary branches |
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(3) |
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Inflorescence consisting of 1-sided spikes or
racemes, these either digitate or scattered along a
central axis, rarely solitary; the racemes sometimes
with short secondary branchlets (Echinochloa
crus-galli) or with the spikelets long-pedicelled
and distant (Brachiaria deflexa) |
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(5) |
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| 3 (2) |
Upper floret coriaceous to crustaceous; lower lemma entire at the tip, awnless; lower glume ± ovate, distinct (if spikelet with a bead-like swelling at the base see 59. Eriochloa) |
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Panicum |
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Upper floret thinly cartilaginous; lower lemma often bibbed at the tip or awned |
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(4) |
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| 4 (3) |
Upper floret dorsally compressed, the stigmas emerging terminally; lower glume very small or suppressed |
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Tricholaena |
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Upper floret laterally compressed, the stigmas emerging laterally; lower glume ± linear to oblong, small |
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Rhynchelytrum |
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| 5 (2) |
Lower glume awned |
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Oplismenus |
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Lower glume at most with a short awn-point |
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(6) |
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| 6 (5) |
Spikelet with a bead-like swelling at its base, formed from the swollen lowest rhachilla-internode covered by the thin lower glume |
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Eriochloa |
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Spikelet passing smoothly into the pedicel without a bead-like swelling |
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(7) |
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| 7 (6) |
Upper lemma coriaceous to crustaceous, with narrow
inrolled margins clasping only the edge of the palea |
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(8) |
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Upper lemma chartaceous to cartilaginous |
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(12) |
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| 8 (7) |
Lower glume present |
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(9) |
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Lower glume absent |
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Paspalum |
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| 9 (8) |
Racemes mostly 4-rowed, the spikelets in clusters of 2 or more; spikelets gibbously plano-convex, cuspidate to awned; upper lemma acute, muticous; upper palea acute, with reflexed tip |
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Echinochloa |
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Racemes mostly 1-2-rowed, the spikelets single or
paired (rarely more) |
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(10) |
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| 10 (9) |
Upper palea obtuse, its tips not reflexed |
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(11) |
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Upper palea acute, its tip reflexed; lower glume turned away from the rhachis |
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Paspalidium |
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| 11 (10) |
Upper lemma at most obscurely mucronulate; spikelets plump, obtuse to acute; lower glume up to half as long as spikelet, turned towards the rhachis (visible in racemes bearing spikelets singly) |
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Brachiaria |
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Upper lemma obtuse with a mucro 0.3-1.2 mm long; spikelets usually much exceeding the upper floret, cuspidate to acuminate; lower glume turned away from the rhachis (visible in racemes bearing spikelets singly |
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Urochloa |
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| 12 (7) |
Upper lemma with narrow inrolled margins clasping only the edge of the palea, its tip awned; racemes
usually in a single whorl |
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Alloteropsis |
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-Upper lemma with thin flat margins covering most of the palea and often overlapping, awnless |
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Digitaria |
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| 13 (1) |
Bristles persisting on the axis after the spikelets
have fallen |
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Setaria |
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Bristles or spines falling with the spikelets |
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(14) |
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| 14 (13) |
Involucral bristles free throughout, ± filiform |
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Pennisetum |
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Involucral bristles flattened and connate below, commonly forming a cup |
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Cenchrus |
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List of lower taxa
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Treatments in Other Floras @ www.efloras.org
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