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Pacific brome

corn brome, hairy corn brome, squarrose brome

Habit Plants perennial; not rhizomatous. Plants annual.
Culms

60-170 cm, erect;

nodes (5)6-8, pubescent;

internodes usually glabrous, sometimes pubescent near the nodes.

20-60 cm, erect or geniculately ascending.

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.

Panicles

10-25 cm, open, nodding;

branches ascending, spreading, or drooping.

7-20 cm long, 4-8 cm wide, racemose, open, nodding, often with few spikelets, usually secund;

branches sometimes longer than the spikelets, ascending-spreading, flexuous, slightly curved, usually with 1 spikelet.

Spikelets

20-30 mm, elliptic to lanceolate, terete to moderately laterally compressed, with (4)6-10 florets.

15-70 mm, broadly oblong or ovate-lanceolate, terete to moderately laterally compressed;

florets 8-30, bases concealed at maturity;

rachilla internodes concealed at maturity.

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.

smooth or scabrous;

lower glumes 4.5-7 mm, 3-5(7)-veined;

upper glumes 6-8 mm, 7-veined;

lemmas 8-11 mm long, 2-2.4 mm wide, lanceolate, chartaceous, smooth or scabridulous, 7-9-veined, rounded over the midvein, margins hyaline, 0.6-0.9 mm wide, strongly angled above the middle, not inrolled at maturity, apices acute, bifid, teeth shorter than 1 mm;

awns 8-10 mm, flattened and sometimes twisted at the base, divaricate at maturity, arising 1.5 mm or more below the lemma apices;

anthers 1-1.3 mm.

Caryopses

equaling the paleas, thin, weakly inrolled or flat.

Lower

sheaths densely pilose;

ligules 1-1.5 mm, hairy, obtuse, erose, ciliolate;

blades 5-15 cm long, 4-6 mm wide, densely pilose on both surfaces.

2n

= 28.

= 14.

Bromus pacificus

Bromus squarrosus

Distribution
from FNA
AK; OR; WA; BC
[WildflowerSearch map]
[BONAP county map]
from FNA
AR; CO; CT; ID; IL; IN; KS; KY; MI; MO; MT; ND; NE; NJ; NM; NY; OR; PA; SD; VT; WA; WI; WY; HI; AB; BC; MB; NT; ON
[WildflowerSearch map]
[BONAP county map]
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 squarrosus grows in overgrazed pastures, fields, waste places, and road verges. Native to central Russia and southern Europe, it can be found mainly in southern Canada and the northern half of the United States.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 24, p. 218. FNA vol. 24, p. 237.
Parent taxa Poaceae > subfam. Pooideae > tribe Bromeae > Bromus > sect. Bromopsis Poaceae > subfam. Pooideae > tribe Bromeae > Bromus > sect. Bromus
Sibling taxa
B. aleutensis, B. anomalus, B. arenarius, B. arizonicus, B. arvensis, B. berteroanus, B. briziformis, B. carinatus, B. caroli-henrici, B. catharticus, B. ciliatus, B. commutatus, B. danthoniae, B. diandrus, B. erectus, B. frondosus, B. grandis, B. hallii, B. hordeaceus, B. inermis, B. japonicus, B. kalmii, B. laevipes, B. lanatipes, B. lanceolatus, B. latiglumis, B. lepidus, B. madritensis, B. maritimus, B. mucroglumis, B. nottowayanus, B. orcuttianus, B. polyanthus, B. porteri, B. pseudolaevipes, B. pubescens, B. pumpellianus, B. racemosus, B. ramosus, B. richardsonii, B. riparius, B. rubens, B. scoparius, B. secalinus, B. sitchensis, B. squarrosus, B. sterilis, B. suksdorfii, B. tectorum, B. texensis, B. vulgaris
B. aleutensis, B. anomalus, B. arenarius, B. arizonicus, B. arvensis, B. berteroanus, B. briziformis, B. carinatus, B. caroli-henrici, B. catharticus, B. ciliatus, B. commutatus, B. danthoniae, B. diandrus, B. erectus, B. frondosus, B. grandis, B. hallii, B. hordeaceus, B. inermis, B. japonicus, B. kalmii, B. laevipes, B. lanatipes, B. lanceolatus, B. latiglumis, B. lepidus, B. madritensis, B. maritimus, B. mucroglumis, B. nottowayanus, B. orcuttianus, B. pacificus, B. polyanthus, B. porteri, B. pseudolaevipes, B. pubescens, B. pumpellianus, B. racemosus, B. ramosus, B. richardsonii, B. riparius, B. rubens, B. scoparius, B. secalinus, B. sitchensis, B. sterilis, B. suksdorfii, B. tectorum, B. texensis, B. vulgaris
Synonyms Bromopsis pacifica
Name authority Shear L.
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