138 CLASSIFICATION OF [CH. 



II. "Seed" long" (Corn and Barley type). Caryopsis 

 oblong or flattened, usually trapped between the 

 boat-shaped palese : if otherwise, with an awn. 



A. "Seed" awnless. There may be a short sharp point 

 to the palea (mucronate), but no prominent hair- or 

 bristle-awn exceeding half the length of the palea. 



(a) A " web " or tuft of hairs at the base or on 

 the rachilla. 



(1) Hairs of basal tuft silky and erect. 



* Pencil of hairs as long as palea or longer. 



Calamagrostis lanceolata, Roth. 



Palea 3 mm. long, thin, two-toothed and with a short 

 bristle at the apex. 



Other species of Calamagrostis are awned. None occurs as an 

 ordinary impurity in "seed." 



Arundo Phragmites, L. 



Palea narrow and long, 10 — 11 mm., delicate, entire, 

 tapering to an acuminate point, violet, three-nerved, 

 smooth. Caryopsis about 2 mm. A pencil of long silky 

 hairs on the rachilla. 



The long acuminate point is almost an awn. 



Calamagrostis also has long basal hairs : both are useless grasses 

 agriculturally. For Glyceria see note, p. 146. Avena, Aira and 

 Psamma are easily distinguished. 



** Pencil of hairs short. 



t Palea mucronate, 11 — 12 mm. long: caryopsis 

 4*5 mm. 



Psamma arenaria. 



