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Pacific brome

brome, chess

Habit Plants perennial; not rhizomatous. Plants perennial, annual, or biennial; usually cespitose, sometimes rhizomatous.
Culms

60-170 cm, erect;

nodes (5)6-8, pubescent;

internodes usually glabrous, sometimes pubescent near the nodes.

5-190 cm.

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.

closed to near the top, usually pubescent;

auricles sometimes present;

ligules membranous, to 6 mm, usually erose or lacerate;

blades usually flat, rarely involute.

Panicles

10-25 cm, open, nodding;

branches ascending, spreading, or drooping.

Inflorescences

panicles, sometimes racemes in depauperate specimens, erect to nodding, open to dense, occasionally 1-sided;

branches usually ascending to spreading, sometimes reflexed or drooping.

Spikelets

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

5-70 mm, terete to laterally compressed, with 3-30 florets;

disarticulation above the glumes, beneath the 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.

unequal, usually shorter than the adjacent lemmas, always shorter than the spikelets, glabrous or pubescent, usually acute, rarely mucronate;

lower glumes 1-7(9)-veined;

upper glumes 3-9(11)-veined;

lemmas 5-13-veined, rounded to keeled, glabrous or pubescent, apices entire, emarginate, or toothed, usually terminally or subterminally awned, sometimes with 3 distinct awns or unawned;

paleas usually shorter than the lemmas, ciliate on the keels, adnate to the caryopses;

anthers (2)3.

x

= 7.

2n

= 28.

Bromus pacificus

Bromus

Distribution
from FNA
AK; OR; WA; BC
[WildflowerSearch map]
[BONAP county map]
from FNA
AK; 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; HI; AB; BC; MB; NB; NL; NS; NT; NU; ON; PE; QC; SK; YT; Greenland
[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 grows in temperate and cool regions. It is estimated to include 100-400 species, the number depending on how the species are circumscribed. Of the 52 species in the Flora region, 28 are native and 24 are introduced. The native perennial species provide considerable forage for grazing animals, with some species being cultivated for this purpose. The introduced species, all but three of which are annuals, range from sporadic introductions to well-established members of the region's flora. Many are weedy and occupy disturbed sites. Some are used for hay; others have sharp, pointed florets and long, rough awns that can injure grazing animals.

This treatment is based on one submitted by Pavlick, who died before it could be reviewed and edited. It has been substantially revised by Anderton to meet the requirements for publication in this volume. The majority of Pavlick's taxonomic concepts are retained, despite the necessity for overlap in many key leads; time constraints prevented a thorough investigation of problematic taxa. The treatment recognizes taxa at both the subspecies and varietal rank; this simply reflects the decisions of the original author. We thank Hildemar Scholz of the Botanic Garden and Botanical Museum Berlin-Dahlem, Free University Berlin, for providing accurately identified specimens of the weedy European species for use in preparing the illustrations, and for his helpful suggestions for the keys and descriptions.

In the keys and descriptions, the distances from the bases of the subterminal lemma awns to the lemma apices are measured on the most distal florets in a spikelet.

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

Key
1. Lemmas strongly keeled, at least distally; spikelets strongly laterally compressed; lower glumes 3-7(9)-veined
sect. Ceratochloa
1. Lemmas rounded over the midvein; spikelets terete to moderately laterally compressed; lower glumes 1-5-veined.
→ 2
2. Awns, if present, arising less than 1.5 mm below the lemma apices; lemma apices entire, emarginate, or with teeth less than 1 mm long.
→ 3
3. Lower glumes 1-3-veined; upper glumes 3-5-veined; plants perennial or annual, if annual, the lower glumes 1-veined and the upper glumes 3-veined
sect. Bromopsis
3. Lower glumes 3-5-veined; upper glumes 5-9-veined; plants annual or biennial, if biennial, the upper glumes 7-veined and/or the lateral veins of the lemmas prominently ribbed
sect. Bromus
2. Awns arising 1.5 mm or more below the lemma apices, lemma apices entire, emarginate, or with teeth to 5 mm long.
→ 4
4. Awns usually geniculate, sometimes only divaricate, lemma teeth 2-3 mm long, usually aristate, sometimes only acuminate
sect. Neobromus
4. Awns straight, arcuate, or divaricate, not geniculate, sometimes absent; lemma teeth absent or to 5 mm long, acuminate.
→ 5
5. Lower glumes 1-3-veined; upper glumes 3-5-veined; spikelets with parallel or diverging sides in outline, often widening distally; lemma apices bifid, teeth (0.8)1-5 mm long
sect. Genea
5. Lower glumes 3-5-veined; upper glumes 5-9-veined; spikelets with parallel or converging sides in outline; lemma apices entire to bifid, teeth less than 1 mm long, apices sometimes split and teeth appearing longer
sect. Bromus
Source FNA vol. 24, p. 218. FNA vol. 24, p. 193. Author: Leon E. Pavlickf;.
Parent taxa Poaceae > subfam. Pooideae > tribe Bromeae > Bromus > sect. Bromopsis Poaceae > subfam. Pooideae > tribe Bromeae
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
Subordinate taxa
B. sect. Bromopsis, B. sect. Bromus, B. sect. Ceratochloa, B. sect. Genea, B. sect. Neobromus
Synonyms Bromopsis pacifica
Name authority Shear L.
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