SEEDS OF QUACK-GRASS AND OF CERTAIN WHEAT-GRASSES. 9 



SUMMARY. 



(1) Seed of qiuick-grass is a common impurity of certain kinds of 

 commercial seed, especially of the seed of awnless brome-grass 

 (Bromus inermis). 



(2) Quack-grass seed appears in all lots of brome-grass seed im- 

 poit(Ml from Europe and may occur in brome-grass seed produced in 

 Canada or the Western States. 



(3) Brome-grass seed i)roduced in Canada or the United States 

 often contains seed of wheat-grasses, which is likely to be mistaken 

 for quack-grass seed. It is therefore desirable to distinguish between 

 quack-grass seed and the similar seed of the wheat-grasses. 



(4) Seeds of quack-grass in brome-giass seed appear chie% as 

 whole or partial spikelets, while few such spikelets of the wheat- 

 grasses occur in sam])les containing seed of these grasses. 



(5) The most evident identifying characters of quack-grass and 

 wheat-grass seeds appear in the spikelets and their glumes. 



(6) While it is usually possible to determine which kind of Agro- 

 pyron is in a sample of seed, the presence or absence of quack-grass 

 seed with reference to awnless brome-grass seed should be determin- 

 able without difficulty. 



Approved : 



James Wilson, 



Secretary of Agriculture. 



Washington, D. C, October 28, 1910. 



[Cir. 73] 



O 



