150 



CLASSIFICATION OF 



[CH. 



No keel. Apex of inner palea bifid, outer mucronate. 

 Fruit shelled. 



Easily distinguished from Digraphis arundinacea, which has 

 a basal hair-tuft and very different caryopsis ; less easily from 

 Agropyrum and LoUum, except in the velvety surface. 



Fig. 63. Elymus aren- 

 aritis. a, " seed," 

 nat. size; h and c, 

 the same, x 3. Note 

 the stifi, velvety, bifid 

 and mucronate outer 

 palea, and the large 

 hairy rachilla. Nobbe. 



Fig. 64. Bactylis glomerata. a, spikelet 

 ■with glumes removed, nat. size; 6, 

 ditto, X about 6; c and d, " seed," nat. 

 size (below) and x about 6. The sti£f 

 and slightly curved awn-point is sub- 

 terminal and arises from between two 

 teeth. Kachilla dilated above. Nobbe. 

 Of. Fig. 60. 



Agropyrum repens may have a mucronate awn-point 

 or not. The small palea 10 — 12, the caryopsis 5 — 6 mm. 

 (see p. 169 for description). 



This troublesome weed (Couch-grass) presents similar difficulties 

 with Lolium perenne that AgropyruT/i caninum does with Lolium 

 termdentum — see p. 168. It is moreover extremely variable. 



