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Tristachya avenacea (J. Presl) Scribn. & Merr.

Comprehensive Description

provided by North American Flora
Tristachya avenacea (Presl) Scribn. & Merr. Bull. U. S. Dep Agr. Agrost. 24: 23. 1901.
Monopogon avenaceus Presl, Rel. Haenk. 1: 325. 1830.
Tristachya mexicana Kunth, R^v. Gram. Suppl. XXVI. 1830. (Based on Monopogon avenaceus Presl.)
Culms in tufts, erect, 80-100 cm. tall, the nodes strigose; sheaths, except the lowermost, much shorter than the internodes, sparsely appressed-hirsute to glabrous; ligule a ring of stiff hairs less than 1 mm. long; blades flat to subinvolute, elongate, spreading to reflexed, flexuous in age, 3-5 mm. wide, sometimes hirsute on the upper surface toward the base, the margins scabrous; panicle erect, the slender scabrous axis 6-15 cm. long, the rather distant appressed to ascending branches 0.5-3.5 cm. long, scabrous; spikelets brown, the triad, excluding the awns, 3-3.5 cm. long; first glume 1.7-2.2 cm. long, minutely ciliate at the obscurely toothed apex; second glume about 3 cm. long, tapering to a narrow, ciliolate, truncate or minutely lobed apex; sterile lemma a little longer than the first glume and similar to it ; fertile lemma villous, especially toward the base, 8-9 mm. long, including the bearded callus and the short acuminate teeth; awn 4-7 cm. long, twisted about half its length, the terminal segment flexuous.
Type locality: Mexico (Haenke).
Distribution: Hills and wooded slopes, Jalisco and Oaxaca.
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bibliographic citation
Albert Spear Hitchcock, Jason Richard Swallen, Agnes Chase. 1939. (POALES); POACEAE (pars). North American flora. vol 17(8). New York Botanical Garden, New York, NY
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