SCATTERING OP WEEDS 



639 



Fig. 503. Seeds of Poas with impurities. 1, Kentucky Blue Grass rubbed and 

 unrubbed ; 2, Wood Meadow Grass (Poa nemoralis) ; 3, Ergot, a fungus; 

 4, Texas Blue Grass (P. arachnifera) ; 5, Canadian Blue Grass (Poa 

 compressa) ; 6, Rough Stalked Meadow Grass (Poa trivialis) ; 7, Silky Bent 

 Grass (Apera spica-venti) ; 8, Wood Hair Grass (Deschampsia flexuosa) ; 

 9, spine of Canada Thistle; 10, Canada Thistle; 11, caryopsis of Stink 

 Grass (Eragrostis major). 



(U. S. Dept. Agr.) 



