Family: Poaceae
Poverty Three-Awn
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Kelly W. Allred Plants perennial; cespitose. Culms 25-70 cm, erect or prostrate, unbranched or sparingly branched. Leaves tending to be basal; sheaths longer than the internodes, glabrous except at the summit; collars densely pilose; ligules 0.5-1 mm; blades 5-20 cm long, 1-2 mm wide, flat to loosely involute, glabrous. Inflorescencespaniculate, 10-30 cm long, 6-25 cm wide, peduncles flattened and easily broken; rachis nodes glabrous or with hairs, hairs to 0.5 mm; primary branches 5-13 cm, stiffly divaricate to reflexed, with axillary pulvini, usually naked on the basal 1/2; secondary branches usually well-developed. Spikelets overlapping, usually appressed, sometimes divergent and the pedicels with axillary pulvini. Glumes 8-12 mm, 1-veined, acuminate or shortly awned, awns to 4 mm; calluses about 0.5 mm; lemmas 8-13 mm long, the terminal 2-3 mm with 4 or more twists when mature, narrowing to 0.1-0.2 mm wide just below the awns, junction with the awns not evident; awns (7)10-20 mm, not disarticulating at maturity; central awns almost straight to curved at the base, ascending to somewhat divergent distally; lateral awns slightly thinner and from much to slightly shorter than the central awns, ascending to divergent; anthers 3, 0.8-1 mm. Caryopses 8-10 mm, light brown. 2n = 22. Aristida divaricata grows on dry hills andplains, especially in pinyon-juniper-grassland zones, from the southwestern United States through Mexico to Guatemala. It occasionally intergrades with A. havardii, but that species has lemma beaks that are straight or have only 1-2 twists, shorter primary branches, usually no secondary branches, and pedicels that more frequently have axillary pulvini so the spikelets are more frequently divergent than in A. divaricata. Beetle, A.A. 1983. Las Gramíneas de México I Culmos amacollados de 30 a 60 cm o más de alto, erectos, o postrados y extendidos; vainas redondeadas, glabras o escaberulosas hacia el collar, éste puberulento en ambos lados, la garganta generalmente vellosa; lígula un penacho denso de vellos suaves; láminas por lo regular ligeramente involutas, en ocasiones planas, las basales fuertemente involutas, usualmente de menos d 3 mm de ancho y hasta 20 cm de largo. Panícula abierta, de 10 a 30 cm de largo, las ramificaciones primarias abiertas y desnudas en la base, hasta de 15 cm de largo, ramificándose 2 ó 3 veces, las últimas ramificaciones y pedicelos comprimidos hacia la primaria; glumas casi iguales, de 10 a 12 mm de largo, acuminadas y corto-aristadas, 1-nervadas, la primera escabrosa en la quilla; lema de 10- a 12 mm de largo, glabra hacia la base, escabrosa hacia el ápice, callo densamente vellosa; columna retorcida de 2 a 5 mm de largo, en ocasiones superando a las glumas; aristas aproximadamente iguales, algo divergentes, escabrosas, rectas en la base, de 10 a 15(-18) mm de longitud; n = 11. Descrita de la parte central de México; crece en suelos arenosos, en lomas y planicies secas, bosques aciculifolios, esclerófilos y en pastizales abiertos. Kansas y Texas hacia Arizona, partes Norte y central de México; de valor forrajero regular. |