THE SEEDS OF THE GRASSES. 157 



brown, the hairs on the rachilla are slender, and the grain is 

 grooved. In A. pratensis the rachilla hairs are stout. 



Brachypodium. — The palea of B. sy.lvaticum is straw-coloured, 

 ribbed, and hairy and has a long terminal awn, the rachilla is 

 smooth and stout, and the grain has a shallow groove. The palea 

 of B. pinnatum is boat-shaped, the awn is smooth and short, and 

 the grain is slender. 



Briza. — The seed is ovoid and dark brown in both species ; 

 that of B. media being the larger. 



Bromus. — In B. erectus the palea is flat above and incurved 

 below ; the awn is long, narrow, smooth, and stiff ; the rachilla 

 is long and thin ; and the grain is purplish brown, flat, long, 

 pointed at both ends, with remains of the stigma on the sides near 

 the tip. In B. asper the grain is reddish, long and narrow. 

 The palea in B. sterilis is reddish brown, with a long, serrulate 

 awn ; the grain is narrow and flat, and the rachilla is flat and 

 tapers downwards. In B. arvensis and its varieties the palea is 

 oblong with ciliate ribs, the awn is smooth, and the grain is flat 

 and thin. In B. giganteus the awn is long and sub-terminal 

 and serrulate, the rachilla is bristly and so is the base, and the 

 grain is thin, flat, and glabrous, but shorter than in B. erectus. 



Calamagrostis. — C. epigeios has a tuft of long silky hairs at 

 the base of the palea which is bifid at the tip, and the awn is 

 slender and dorsal. In C. lanceolata the awn is less than half 

 the length of the palea, which has a tuft of hairs at the base. 



Catabrosa. — In C. aquatica the palea is not winged or in- 

 flated but broad and flat. 



Digraphis. — The grain of D. arundinacea is free ; it is dark 

 greyish brown, long, flat, finely dotted, and without a groove. 



Elymus. — The seed of E. arenarius is about half an inch long, 

 whitish, and rather narrow, the palea being stiff, pubescent, and 

 pointed ; the rachilla is large and hairy. 



Festuca. — In addition to the species mentioned above it 

 should be said that the grain of F. myurus is mammillate upwards 

 and the rachilla small. 



Holcus. — The seed of H. mollis can be distinguished from 

 that of H. lanatus by the awn, which is kneed instead of hooked. 



