Bromus racemosus |
Bromus arizonicus |
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bald brome, brome a grappes, smooth brome |
Arizona brome |
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Habit | Plants annual. | Plants annual; tufted. |
Culms | 20-110 cm, erect or ascending. |
30-90 cm tall, to 3 mm thick, erect. |
Sheaths | 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. |
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Panicles | 4-16 cm long, 2-3 cm wide, erect, open; branches sometimes longer than the spikelets, slender, usually ascending, slightly curved or straight. |
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. |
Spikelets | 12-20 mm, lanceolate, terete to moderately laterally compressed; florets 5-6, bases concealed at maturity; rachilla internodes 1-1.5 mm, concealed at maturity. |
18-25 mm, elliptic to lanceolate, strongly laterally compressed, with 4-8 florets. |
Glumes | smooth to scabrous; lower glumes 4-6 mm, (3)5-veined; upper glumes 4-7 mm, 7-veined; lemmas 6.5-8 mm long, 3-4.5 mm wide, elliptic to lanceolate, coriaceous, backs smooth, distinctly 7(9)-veined, not ribbed, rounded over the midvein, margins scabrous, rounded, not inrolled at maturity, apices acute to obtuse, bifid, teeth shorter than 1 mm; awns 5-9 mm, all more or less equal in length, straight, arising less than 1.5 mm below the lemma apices; anthers 1.5-3 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. |
Caryopses | shorter than the paleas, thin, weakly inrolled or flat. |
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Lower | sheaths densely hairy, hairs stiff, often retrorse; upper sheaths glabrous or pubescent; ligules 1-2 mm, glabrous or hairy, erose; blades 7-18 cm long, 1-4 mm wide, pilose on both surfaces. |
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2n | = 28. |
= 84. |
Bromus racemosus |
Bromus arizonicus |
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Distribution |
AK; AL; AR; AZ; CA; CO; CT; DC; DE; FL; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MO; MS; MT; NC; ND; NE; NH; NJ; NM; NV; NY; OH; OK; OR; PA; RI; SC; TN; TX; UT; VA; VT; WA; WI; WV; WY; AB; BC; LB; NB; NS; NT; ON; PE; QC; SK
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AZ; CA; NV; TX
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Discussion | Bromus racemosus grows in fields, waste places, and road verges. It is native to western Europe and the Baltic region, and occurs throughout much of southern Canada and the United States. Hitchcock (1951) included B. hordeaceus subsp. pseudothominei in B. racemosus. (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.) |
Source | FNA vol. 24, p. 233. | FNA vol. 24, p. 201. |
Parent taxa | Poaceae > subfam. Pooideae > tribe Bromeae > Bromus > sect. Bromus | Poaceae > subfam. Pooideae > tribe Bromeae > Bromus > sect. Ceratochloa |
Sibling taxa | ||
Synonyms | B. berteroanus var. excelsus | |
Name authority | L. | (Shear) Stebbins |
Web links |
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