Source:
SSA
Description:
Annual or perennial, tufted, rhizomatous, sometimes geniculate. Leaf blade linear to linear-lanceolate, expanded; ligule a conspicuous, unfringed membrane. Inflorescence a dense, oblong or spike-like panicle, sometimes subcapitate or interrupted and lobed, ( P. paradoxa: 1 fertile spikelet surrounded by 5 or 6 sterile spikelets, these often reduced to clavate knobs; the whole falling as a unit); spikelets shortly pedicelled. Spikelet strongly laterally compressed, disarticulating above glumes; glumes +/- equal, completely enclosing lemma, membranous, boat-shaped, almost plano-convex in outline, subobtuse, 3-nerved, strongly keeled, keels often winged and toothed. Florets 3, lowest 2 florets sterile, reduced to rudimentary lemmas, varying from very small to more than half as long as upper lemma, glabrous; uppermost floret bisexual; lemma firmer than glumes, chartaceous, ovate-elliptic or ovate-lanceolate, usually softly hairy, 5-nerved, obtuse or acute, awnless; palea relatively long, keelless. Lodicules 2, membranous, hyaline. Stamens 3. Ovary ellipsoid; styles distinct, plumose. Caryopsis ellipsoid. x= 6, 7 (aneuploids, high polyploidy).
Distribution:
Species +/- 16, north temperate, but mostly from Mediterranean region, also South America; 6 in sthn Afr., widespread weeds or escapes from cultivation.
Classification:
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