t$6 THE SEEDS OF THE GRASSES. 



grooved on the ventral surface. Yorkshire fog is often found as 

 an adulterant with meadow foxtail and sometimes with rye grass, 

 but is quite as recognisable as yellow oat when used in a similar 

 way with cock's-foot. 



The foregoing being all the seeds likely to be met with in 

 sorting out a purchased mixture, we may now briefly deal with 

 those we may come across in the field as helping in however slight 

 a degree in the identification of the plant. 



Agropyrum. — The seed of A. repens is of the same character 

 as that of wheat ; boat-shaped, greyish brown, hairy above, 

 rounded on the back, and slightly grooved; the rachilla tapers 

 downwards ; the awn of the outer palea when present is short. 

 That of A. caninum is similar but has a longer awn. 



Agrostis. — The seed of A. canina differs from that of A. alba, 

 already described, in being larger and the palea being punctate 

 and awned ; that of A . spica-venti has a few silky hairs at the 

 base of the outer palea. 



Aira. — In A. ccsspitosa the palea is toothed and awned, 

 the rachilla is hairy, and there is a ring of hairs at the base of 

 the seed ; the grain is white and shining. In A . flexuosa the 

 palea has four teeth at the apex and a dorsal awn near the base, 

 and there are basal hairs ; the grain is grooved and dark in colour. 

 The awn in A. canescens is bearded in the middle and thick and 

 white above ; the grain is yellow, polished, and small. A . pvcecox 

 has a short awn and no basal hairs. A. caryophyllea has a thin, 

 dark, twisted awn twice as long as the palea, not bearded or 

 thickened, and the seed is comma-shaped and dark brown. 



Alopecurus. — The seeds of A. geniculates are similar to 

 those of meadow foxtail, but the glumes are more open and not 

 so pointed. 



Arrhenatherum. — In A. avenaceum the palea has a tuft of 

 hairs at the base, the longer awn is dark brown marked with a 

 pale spiral band ; the grain is pale brown, fusiform, and has no 

 groove. 



Arundo. — The seed of A. phragmites is pale purple, long, 

 pointed, and smooth ; the rachilla has silky hairs at the base. 



Avena. — In A. fatua the palea has yellow hairs, the awn is 



