56 



MISC. PUBLICATION 200, U. S. DEPT. OF AGRICULTURE 



sheaths and blades pubescent ; panicle 

 5 to 15 cm. long, rather dense, soft, 

 drooping, often purple ; spikelets nod- 

 ding, 12 to 20 mm. long; glumes 

 villous, the first 4 to 6 mm. long, the 

 second 8 to 10 mm. long; lemmas 

 lanceolate, villous or pilose, 10 to 12 

 mm. long, the teeth 2 to 3 mm. long; 

 awn 12 to 14 mm. long. O — Along 

 roadsides, banks, and waste places, 

 common on the Pacific coast, espe- 

 cially in Washington and Oregon ; Al- 

 berta, and here and there throughout 

 the United States as far south as 

 South Carolina and Texas. Bromtjs 

 tectorum var. glabratus Spenner. 

 Differing in having glabrous spike- 

 lets. O (B. tectorum var. nudus 

 Klett and Richter.) — About the same 

 range as the species, less common. 



Section 5. Neobr6mtjs Shear, as subgenus. 



Annual; lemmas lanceolate, deeply 

 bifid, the teeth aristate; awn 

 twisted, geniculate. Approaches 

 Trisetum. 



Figure 41. — Bromus trinii, X 1. (Eastwood, Calif.) 



42. Bromus trinii Desv. Chilean 

 chess. (Fig. 41.) Culms 30 to 60 

 cm. or even 100 cm. tall, erect or 

 branched and spreading below, often 

 pubescent at the nodes; sheaths and 

 blades pilose-pubescent to nearly 

 smooth; panicle 8 to 20 cm. long, 

 narrow, rather dense, erect, the 

 branches erect or the lower more or 

 less spreading or flexuous; spikelets 

 narrow, 1.5 to 2 cm. long, 5- to 7- 

 flowered; glumes lanceolate, acumi- 



nate, the first mostly 1-nerved, 8 to 

 10 mm. long, the second mostly 3- 

 nerved, 12 to 16 mm. long; lemmas 

 5-nerved, 12 to 14 mm. long, pubes- 

 cent, acuminate, with narrow teeth 

 2 to 3 mm. long, the teeth aristate; 

 awn 1.5 to 2 cm. long, twisted below, 

 bent below the middle and strongly 

 divaricate when old. O (Includ- 

 ing B. trinii var. pallidiflorus Desv.) 

 — Dry plains and rocky or wooded 

 slopes, Oregon, California, and Baja 

 California, rarely eastward to Colo- 

 rado; introduced from Chile. 



Bromus trinii var. excelstjs 

 Shear. Differing in having larger 

 spikelets, 7-nerved lemmas, and di- 

 varicate but not twisted or bent 

 awns; teeth of the lemma acuminate, 

 but not aristate. O — A little- 

 known form from the Panamint 

 Mountains, Calif., and Emory Can- 

 yon, Lake Mead, Ariz. 



3. BRACHYPODIUM Beauv. 



Spikelets nearly sessile, several- to 

 many-flowered, the rachilla disartic- 

 ulating above the glumes and be- 

 tween the florets; glumes unequal, 

 sharp-pointed, 5- and 7-nerved; lem- 

 mas firm, rounded or somewhat flat- 

 tened on the back, 7-nerved, acumi- 

 nate, awned or mucronate; palea as 

 long as the body of the lemma, con- 

 cave, the keels pectinate-ciliate. An- 

 nuals or perennials with erect racemes 

 of subsessile spikelets. Type species, 

 Bronms pinnatus L. (Br achy podium 

 pinnatum (L.) Beauv.) Name from 

 brachys, short, and podion, foot, al- 

 luding to the very short pedicels. 



Eurasian species introduced in the 

 United States; two American species 

 only; Mexico to South America. 



1. Brachypodium distachyon (L.) 

 Beauv. (Fig. 42.) Annual, branching 

 and geniculate at base, 15 to 30 cm. 

 tall; nodes pubescent; sheaths and 

 blades sparsely pilose to subglabrous; 

 ligule, 1.5 to 2 mm. long, pubescent; 

 blades flat, 2 to 6 cm. long, 3 to 4 

 mm. wide; raceme strict, the seg- 

 ments of the axis alternately con- 



