Bromus pacificus |
Bromus aleutensis |
|
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Pacific brome |
Aleut brome, Aleutian brome |
|
Habit | Plants perennial; not rhizomatous. | Plants perennial; loosely cespitose. |
Culms | 60-170 cm, erect; nodes (5)6-8, pubescent; internodes usually glabrous, sometimes pubescent near the nodes. |
40-130 cm tall, 3-7 mm thick, often decumbent. |
Sheaths | pilose, midrib of the culm leaves not abruptly narrowed just below the collar; auricles absent; ligules 2-4 mm, glabrous, truncate, erose or lacerate; blades 20-35(37) mm long, 6-16 mm wide, flat, abaxial surfaces glabrous, adaxial surfaces pilose. |
coarsely striate, pilose, hairs sparse to moderately dense, throats pilose; auricles rarely present; ligules 3.5-5 mm, usually glabrous, occasionally pubescent, lacerate; blades 13-35 cm long, 6-15 mm wide, flat, usually sparsely to moderately pilose on both surfaces, sometimes glabrous. |
Panicles | 10-25 cm, open, nodding; branches ascending, spreading, or drooping. |
10-28 cm, erect, open or somewhat contracted; lower branches to 10 cm, 1-2 per node, stiffly ascending, with (1)2-3 spikelets on the distal 72, sometimes confined to the tips. |
Spikelets | 20-30 mm, elliptic to lanceolate, terete to moderately laterally compressed, with (4)6-10 florets. |
25-40 mm, elliptic to lanceolate, strongly laterally compressed, with 3-6 florets. |
Glumes | pubescent; lower glumes 6-8.5 mm, 1(3)-veined; upper glumes 8-11.5 mm, 3-veined, not mucronate; lemmas 10-12 mm, lanceolate, rounded over the midvein, backs pubescent, margins more densely so, apices acute, entire; awns 3.5-7 mm, straight, arising less than 1.5 mm below the lemma apices; anthers 2-4 mm. |
glabrous or pubescent; lower glumes 9-13 mm, 3-5-veined; upper glumes 10-15 mm, 7(9)-veined; lemmas 12-17 mm, lanceolate, laterally compressed, usually softly pubescent, sometimes glabrous, strongly keeled at least distally, 9(11)-veined, veins conspicuous distally, apices entire or with acute teeth shorter than 1 mm; awns (3)5-10 mm; anthers 2.2-4.2 mm. |
2n | = 28. |
= 56. |
Bromus pacificus |
Bromus aleutensis |
|
Distribution |
AK; OR; WA; BC
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AK; WA; AB; BC; ON; QC |
Discussion | Bromus pacificus grows in moist thickets, openings, and ravines along the Pacific coast from southeastern Alaska to northern California, with a few occurrences further inland. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Bromus aleutensis grows in sand, gravel, and disturbed soil along the Pacific coast, from the Aleutian Islands of Alaska to western Washington, and on some lake shores of central British Columbia. It has also been found further east in Canada and in northern Idaho, always in disturbed sites, such as road edges. Bromus aleutensis might represent a modified version of B. sitchensis, in which reproduction occurs at a relatively early developmental state in response to the climatic conditions of the Aleutian Islands (Hulten 1968). B. aleutensis is predominantly self-fertilizing, and B. sitchensis is predominantly outcrossing. Anther lengths close to 4.2 mm suggest that at least some plants of B. aleutensis are outcrossing (Hitchcock 1969). Bromus aleutensis intergrades with B. carinatus var. marginatus to the south. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 24, p. 218. | FNA vol. 24, p. 203. |
Parent taxa | Poaceae > subfam. Pooideae > tribe Bromeae > Bromus > sect. Bromopsis | Poaceae > subfam. Pooideae > tribe Bromeae > Bromus > sect. Ceratochloa |
Sibling taxa | ||
Synonyms | Bromopsis pacifica | B. sitchensis var. aleutensis |
Name authority | Shear | Trin. ex Griseb. |
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