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Mexican brome

rattlesnake brome, rattlesnake chess, rattlesnake grass

Habit Plants perennial; not rhizomatous. Plants annual.
Culms

40-90 cm, erect;

nodes (3)4-7(8), these and the internodes pubescent or glabrous.

20-62 cm, erect or ascending.

Sheaths

glabrous or pilose, midrib of the culm leaves abruptly narrowed just below the collar;

auricles often present on the lower leaves;

ligules to 1 mm, truncate;

blades 14-22(26) cm long, to 6 mm wide, flat, glabrous or pilose, not glaucous.

densely pilose;

ligules 0.5-2 mm, hairy, obtuse, erose;

blades 3-13 cm long, 2-4 mm wide, pilose to pubescent on both surfaces.

Panicles

10-20 cm, open, nodding;

branches ascending or spreading.

5-15 cm long, 3-7 cm wide, open, secund, nodding;

branches sometimes longer than the spikelets, curved to reflexed.

Spikelets

(14)15-30 mm, elliptic to lanceolate, terete to moderately laterally compressed, with 4-12 florets.

15-27 mm long, 8-12 mm wide, ovate, laterally compressed;

florets 7-15, bases concealed at maturity;

rachilla internodes concealed at maturity.

Glumes

usually pubescent, rarely glabrous;

lower glumes 5-6 mm, 1-3-veined;

upper glumes 6-8 mm, 3-veined, sometimes mucronate;

lemmas 7-10 mm, elliptic to lanceolate, rounded over the midvein, backs and margins pubescent, apices acute to obtuse, entire;

awns 1-3(5) mm, straight, arising less than 1.5 mm below the lemma apices;

anthers 2-4 mm.

smooth or scabridulous;

lower glumes 5-6 mm, 3-5-veined;

upper glumes 6-8 mm, 7-9-veined;

lemmas 9-10 mm long, 6-8 mm wide, inflated, obovate or rhombic, coriaceous, smooth or scabridulous, obscurely 9-veined, rounded over the midvein, margins hyaline, 1-1.3 mm wide, abruptly angled, not inrolled at maturity, apices acute to obtuse, bifid, teeth shorter than 1 mm;

awns usually absent, sometimes to 1 mm, arising less than 1.5 mm below the lemma apices;

anthers 0.7-1 mm.

Caryopses

equaling or shorter than the paleas, thin, weakly inrolled or flat.

2n

= 14.

= 14.

Bromus anomalus

Bromus briziformis

Distribution
from FNA
NM; TX; AB; BC; SK
[BONAP county map]
from FNA
AK; CA; CO; CT; DE; ID; IL; IN; MA; MD; MI; MT; ND; NE; NJ; NM; NV; NY; OH; OR; PA; SD; UT; VT; WA; WY; BC; ON
[WildflowerSearch map]
[BONAP county map]
Discussion

Bromus anomalus grows on rocky slopes in western Texas and adjacent Mexico. Many records of this species in the Flora region are here treated as B. porteri, a closely related species that has sometimes been included in B. anomalus. The main difference is that B. anomalus has auricles, and culm leaves with midribs that are narrowed just below the collar.

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

Bromus briziformis grows in waste places, road verges, and overgrazed areas. It is native to southwest Asia and Europe, and is adventive in the Flora region, occurring from southern British Columbia to as far south as New Mexico, and in scattered locations eastward. The unique shape of its spikelets has led to its use in dried flower arrangements and as a garden ornamental. The common name may refer to the similarity of the spikelets to a rattlesnake's tail.

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

Source FNA vol. 24, p. 213. 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. 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. squarrosus, B. sterilis, B. suksdorfii, B. tectorum, B. texensis, B. vulgaris
B. aleutensis, B. anomalus, B. arenarius, B. arizonicus, B. arvensis, B. berteroanus, 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 B. brizaeformis
Name authority Rupr. ex E. Fourn. Fisch. & C.A. Mey.
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