Bromus anomalus
Bromus arizonicus
Mexican brome
Arizona brome
40-90 cm, erect;
nodes (3)4-7(8), these and the internodes pubescent or glabrous.
30-90 cm tall, to 3 mm thick, erect.
glabrous or pilose, midrib of the culm leaves abruptly narrowed just below the collar;
auricles often present on the lower leaves;
ligules to 1 mm, truncate;
blades 14-22(26) cm long, to 6 mm wide, flat, glabrous or pilose, not glaucous.
retrorsely pilose, sometimes mostly glabrous, throats sometimes with hairs;
auricles absent;
ligules 1-4 mm, usually glabrous, obtuse, erose;
blades 8-18 cm long, 3-9 mm wide, flat, sparsely pilose on both surfaces or the abaxial surfaces glabrous.
10-20 cm, open, nodding;
branches ascending or spreading.
12-25 cm, somewhat contracted or open;
lower branches shorter than 10 cm, 2-3(5) per node, initially erect to ascending, spreading at maturity, with 1-2 spikelets variously distributed.
(14)15-30 mm, elliptic to lanceolate, terete to moderately laterally compressed, with 4-12 florets.
18-25 mm, elliptic to lanceolate, strongly laterally compressed, with 4-8 florets.
usually pubescent, rarely glabrous;
lower glumes 5-6 mm, 1-3-veined;
upper glumes 6-8 mm, 3-veined, sometimes mucronate;
lemmas 7-10 mm, elliptic to lanceolate, rounded over the midvein, backs and margins pubescent, apices acute to obtuse, entire;
awns 1-3(5) mm, straight, arising less than 1.5 mm below the lemma apices;
anthers 2-4 mm.
subequal, smooth or scabrous;
lower glumes 8-12.5 mm, 3-veined;
upper glumes 9.5-14 mm, 7-veined, about as long as the lowest lemma;
lemmas 9.5-14 mm, lanceolate, laterally compressed, prominently 7-veined, strongly keeled at least distally, glabrous or pubescent distally or throughout, marginal hairs, if present, longer than those elsewhere, apices entire or with acute teeth shorter than 1 mm;
awns 6-13 mm, sometimes slightly geniculate;
anthers 0.4-0.5 mm.
= 14.
= 84.
Bromus anomalus
Bromus arizonicus
Bromus anomalus grows on rocky slopes in western Texas and adjacent Mexico. Many records of this species in the Flora region are here treated as B. porteri, a closely related species that has sometimes been included in B. anomalus. The main difference is that B. anomalus has auricles, and culm leaves with midribs that are narrowed just below the collar.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Bromus arizonicus grows in dry, open areas and disturbed ground of the southwest, usually below 2000 m. Its range extends from California and southern Nevada into Arizona, New Mexico, and northern Mexico.
Stebbins et al. (1944) demonstrated that, like Bromus carinatus var. carinatus, B. arizonicus obtained three of its genomes from B. catharticus or a close relative, but the remaining three genomes are not homologous with those in B. carinatus, probably being derived from a species in a section other than Ceratochloa. The small anthers of B. arizonicus strongly suggest that most seed is produced by selfing.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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