20 



Represented iu the herbarium by a single specimen collected by Dr. L. D. Morse 

 along a walk in San Mateo, California, June, 1898. 



3/i. BROMUS HORDEACEUS GLABRESCENS (Ooss.) n. comb. Bromus 

 mollis glabrescens Coss. Fl. Descr. Par. 654. 1845. 



This differs from the species in having the spikelets glabrous or only scabrous 



throughout. 

 Like the species it is introduced on the east and west coasts. 



Specimens Examined. — Delaware: Millsboro (A. Commons 132). District of Columbia: 

 N. E. Washington (F. Blanchard). California: Marin County (Dr. E. Palmer 



2033); New York Falls (G. Hansen 

 2080); San Francisco (Bolander). 

 Oregon: Bonneville (W. M. Canby 

 26). Washington.: Pullman (A. D. E. 

 Ehner 876); no locality (E. P. Shel- 

 don 8205 and G. R.Vasey). 

 4. BROMUS ARVENSIS L. Sp. PI. 

 1 : 77. 1753. Serrafalcus arvensis 

 Pari. Fl. Ital. 1 : 393. 1848. (Fig. 4. ) 



A tufted annual or biennial, somewhat 

 geniculate at the base. Culm nearly 

 or quite glabrous, about 3-6 dm. 

 high. Sheaths densely soft pubescent; 

 ligule about 2 mm. long, lacerate; 

 blades linear, pubescent both sides. 

 Panicle effuse, broad, apex some- 

 what drooping; lotver rays mostly 

 4-8. Spikelets terete-acuminate at 

 first, becoming slightly laterally 

 compressed when old, about 7-11- 

 fiowered, 1.5-2.5 cm. long, 3-4 mm. 

 broad, smooth or minutely scabrous 

 throughout; empty glumes broad; 

 the lower subacute 3-5-nerved, 4-5 

 mm. long; the upper about 7-nerved, 

 obtuse, 5-6 mm. long; flowering 

 glume 7-8 mm. long, broad, obtvise 

 with the broad hyaline margin j)roject- 

 ing slightly into an obtuse angle just 

 above the middle; apex hyaline, 

 emarginate; awn inserted below the 

 apex, 7-10 mm. long, straight or 

 slightly twisted when old; palea shorter 

 than its glume. 

 Type from Europe. 



Introduced into this country in a few 

 localities. Dr. Beal, in "Grasses of 

 North America," reports it from New Jersey and Michigan. The only Ameri- 

 can specimens we have seen are the following: Missouri: Sheffield, common 

 along railroads (B. F. Bush 577 and 588). 

 This can scarcely be satisfactorily separated from B. patulus M & K., which see 

 for the points of difference usually noted. It is also close to B. racenwsm 

 conimutatus. 



Fig. i.— Bromus arvensin: a, empty glumes; b, 

 part of a spikelet with the lower florets open show- 

 ing the palese. 



