IX] " SEEDS " 145 



Agrostis alba, L. (var. stolonifera). 



Palea enclosing the fruit 1'8 — 2 mm. long, white, 

 delicate, membranous, with a blunt notched apex and 

 three (or five) nerves : occasionally there is a fine kneed 

 basal awn, not projecting. 



The glumes may remain attached : the outer has a 

 serrulate keel, and often a violet hue. No awn. About 

 2—3 mm. 



Caryopsis about I'l mm. long, oblong, yellow, corn- 

 shaped, furrowed, shining through. 



A. vulgaris, L., is a variety with slightly smaller 

 fruits, no awn, and usually three nerves to the palea> 

 but they cannot be distinguished with certainty by the 

 " seed." Rachilla obsolete. 



The colour of the glumes may vary considerably and is some- 

 times yellow. 



The absence of awn, rachilla, and basal hairs distinguishes 

 Agrostis from Aira. 



AA Palea membranoics, ribbed, tips scarious. 



Olyceria aquatica. 

 G. fluitans. 



Olyceria aquatica, Sm. 



Palea strongly 5 — 7 ribbed, obtuse and scarious, about 

 4 mm. long. Green with a purple cast. Caryopsis dark- 

 brown, about 2 mm. long. 



Inner palea punctate. Rachilla slender and cylindrical. 



Olyceria fluitans, Br., is very similar, but longer 

 (6 mm.) and more slender ; the palea scabrid with 

 truncate or ragged tips, and the inner palea not punctate. 

 Yellow. (Fig. 46.) 



w. 10 



