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Aristida Linn., Sp. Pl. 1:82. 1753. Gen. Pl., ed. 5, 35. 1754; Henrard in Meded. Rijks-Herb. No. 54. 1926, No. 54A. 1927, No. 54B. 1928, No. 54C. 1933, No. 58. 1929, No. 58A. 1932; Bor, Grasses Burma Ceyl. Ind. Pak. 404. 1960; De Winter in Bothalia 8: 229. 1965; Bor in Towns., Guest & Al-Rawi, Fl. Iraq 9:383. 1968; Bor in Rech. f., Fl. Iran 70: 363. 1970; Tzvelev, Poaceae URSS 615. 1976; Tutin in Tutin et al., Fl. Fur. 5:254. 1980.
Densely tufted perennials or annuals, usually without a rootstock. Leaf blades linear, usually in a basal tuft, but in annual species borne mainly on the culms. Panicle effuse, contracted or spike-like. Spikelets 1-flowered with long scarious glumes; lemma cylindrical or laterally compressed, indurated, glabrous or scabrid, rarely sparsely hairy, the margins convolute or involute, produced into a 3-branched awn (rarely the lateral branches obsolete); awn with or without a column, articulated or not, the branches glabrous or scabrid, never plumose; callus well-developed, obtuse, bifid or acuminate; palea usually less than half as long as the lemma.
A genus of about 260 species in areas of poor dry soils with low rainfall (but scarcely true deserts into which Stipagrostis extends) throughout the tropics and subtropics especially along the Tropics of Cancer and Capricorn; 7 species occur in Pakistan.
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| 1 |
Lemma (or column) not articulated at its summit |
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(2) |
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Lemma or column articulated at the summit and breaking cleanly across when mature |
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(4) |
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| 2 (1) |
Lateral branches of the awn absent or much reduced, or if up to 15 mm long then bristle-like and much finer than the central branch; tip of lemma with a semi-circular bend below the column |
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Aristida abnormis |
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Lateral branches of the awn well developed, if shorter than the central then of similar texture and not bristle-like; lemma straight, without a bend below the column |
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(3) |
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| 3 (2) |
Tufted robust perennial; panicle effuse, often as broad as long; awns 2 cm long; glumes usually awned |
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Aristida cyanantha |
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Annual or short-lived perennial; panicle ± contracted; awns usually less than 2 cm long; glumes never awned |
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Aristida adscensionis |
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| 4 (1) |
Articulation at the top of the column, just below the awns |
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Aristida mutabilis |
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Articulation at the base of the column |
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(5) |
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| 5 (4) |
Lower glume always longer than the upper; base of the callus pointed |
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Aristida funiculata |
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Lower glume shorter than the upper; base of the callus pointed or forked |
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(6) |
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| 6 (5) |
Callus forked at the base, a dwarf plant |
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Aristida hystricula |
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Callus sharp at the tip and curved; plants 20-65 cm tall |
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Aristida triticoides |
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Lower Taxa
Related Synonym(s):
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