166 CLASSIFICATION OF [CH. 



The very slender and long " seed " and caryopsis distinguish this 

 from all but B. erectus, which has a shorter awn. Perhaps the awn 

 is truly terminal : if so it should go with Festuaa Mywrus, &c. (see 

 p. 171). The length varies greatly. 



Bromus giganteus, L. 



Palea 7 mm. long and inrolled, the base and rachilla 

 bristly, indistinctly 5 — 7 nerved, the tip bifid : sub- 

 terminal awn serrulate, 12 — 15 mm. long. 



Caryopsis 4'5 mm. long, flattened, thin, glabrous. 

 The caryopsis is shorter and more ovoid than in other Bromes. 



= = Palea expanded above {ccyracle-sliaped), awn 

 from sinus beHceen two blunt or triangular 

 teeth. 



Bromus arvensis. 



Bromus arvensis, var. mollis, L. (Fig. 73). 



Palea oblong or obovate, somevsrhat flattened above 

 (coracle-shaped), distinctly 5 — 7 ribbed, 8 — 9 mm. long, 

 not hairy, though the ribs may be ciliate. Awn smooth, 

 arising from the depression between two teeth or rounded 

 projections. Caryopsis flattened and thin, 6 x 1"5 mm. ; 

 apt to fall loose from the palese. 



In the variety B. secalinus the awn is usually shorter than the 

 elliptical palea, and originates in the siuus of a notch (Fig. 74) : in 

 B. mollis from between two teeth, and is as long as the obovate palea. 



Bromus maximtcs and B. madritensis are both rare. 



The broader nerved paleas of B. mollis and shorter, fatter 

 caryopsis, as well as the longer awn distinguish it from B. secalinus 

 and B. arvensis. In the other Bromes the palea is more inrolled and 

 the "seed" more slender as a rule. The rachilla is usually bent 

 above into a slight kink. 



The Bromes are an extremely difficult group. The awn is 

 inserted between the two teeth of the palea or just below. The 

 palea smooth or ciliate on the nerves or roughly hairy. The fruit is 



