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Pacific brome

field brome, soft 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.

80-110 cm, erect.

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.

11-30 cm long, 4-20 cm wide, open, erect or nodding;

branches usually longer than the spikelets, ascending to widely spreading, slender, slightly curved or straight.

Spikelets

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

10-25 mm, lanceolate, terete to moderately laterally compressed, often purple-tinged;

florets 4-10, bases concealed or visible at maturity;

rachilla internodes concealed or visible 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.

glabrous;

lower glumes 4-6 mm, 3-veined;

upper glumes 5-8 mm, 5-veined;

lemmas 7-9 mm long, 1.1-1.5 mm wide, lanceolate, obscurely 7-veined, rounded over the midvein, glabrous, coriaceous, margins slightly angled, inrolled or not at maturity, apices acute, bifid, teeth shorter than 1 mm;

awns 6-11 mm, straight, arising at varying distances below the lemma apices;

anthers 2.5-5 mm.

Caryopses

shorter than the paleas, weakly to strongly inrolled.

Lower

sheaths with dense, soft, appressed hairs;

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

blades 10-20 cm long, 2-6 mm wide, coarsely pilose on both surfaces.

2n

= 28.

= 14.

Bromus pacificus

Bromus arvensis

Distribution
from FNA
AK; OR; WA; BC
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; AR; AZ; CA; CO; CT; DC; DE; FL; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; MT; NC; ND; NE; NH; NJ; NM; NV; NY; OH; OK; OR; PA; RI; SC; SD; TN; TX; UT; VA; VT; WA; WI; WV; WY; AB; BC; MB; ON; QC; SK
[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 arvensis grows along roadsides and in fields and waste places at scattered locations in the Flora region. It is native to southern and south-central Europe.

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

Source FNA vol. 24, p. 218. FNA vol. 24, p. 228.
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. 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. squarrosus, B. sterilis, B. suksdorfii, B. tectorum, B. texensis, B. vulgaris
Synonyms Bromopsis pacifica
Name authority Shear L.
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