IX] "seeds" 159 



much grooved, fusiform, 2 — 3 mm. long, glumes unequal, 

 somewhat keeled and rough. 



(2) Aiun dorsal or basal, fine and hair-like, and 

 little or 7iot at all tivisted or kneed. ''Seed'' 

 small. 



* A pencil of silky hairs on base or rachilla. Palea 

 bifid at the tij^. 



t Basal hairs longer than palea, and obscuring the 

 awn. 



Gala.magrostis Epigeios. 



Of little importance, Digraphis has no awn. 



Calamagrostis Epigeios, Roth. 



Palea about 8 mm. long with toothed apex and very 

 thin caryopsis 1 mm. A conspicuous tuft of fine silky 

 hairs, longer than the palea at the base and on the 

 rachilla. 



Awn slender, dorsal, about as long as the palea. 



C. stricta, Nutt. and C. strigosa, Hartm, are rare. 



ft Basal hairs shorter than palea. 



© Awn brown, bearded in the middle, thickened 

 and lohite above. 



Air a canescens. 



The student will find considerable difficulties in the various 

 species of Aira and Agrostis, owing to their small size and variability 

 as regards awn and basal hair-tufts. All these are weeds, but some 

 occur as adulterants. 



Aira canescens, L. 



" Seed " (apart from the aw^n, it is very like Agrostis) 

 I'D — 2 mm., with a very thin, smooth, keeled, two-nerved 



