PERENNIAL FORAGE GRASSES 



75 



Kentucky blue grass is comparatively free from weed seeds, 

 although slender rush, shepherd's purse, chickweed, pepper 

 grass, sorrel, and some other seeds may occur. Kentucky blue 

 grass flowers in May and 

 June, ripening its seed in 

 the latter month. The 

 tendency is to strip the 

 seed while still green, be- 

 cause it is easier both to 

 strip and to clean when 

 harvested green, and be- 

 cause it shatters easily 

 when ripe. This tends to 

 reduce the germinating 

 power, both because seed 

 is unripe and because 

 when harvested unripe it 

 is more likely to ferment 

 during the curing process. 

 The author tested 17 com- 

 mercial samples in 1891 

 whose germinating power Seeds of Poas with impurities . L Kentucky blue 



in soil in the open air 

 ranged from 7.7 to 35.2 

 per cent., while when 

 ripened seed was gathered 

 and carefully dried 80. i 

 per cent, germinated. 1 The 

 standard of germination is 

 now placed at 50 per cent., 



grass (Poa pratensis) rubbed and unrubbed; 2. 

 wood meadow grass (Poa nemoralis\\ 3. ergot; 

 4. Texas blue grass (Poa arachnifera', 5. 

 Canada blue grass (Poa compressa)', 6. rough- 

 stalked meadow grass (Poa frivialis); 7. silky 

 bent grass (Apera spica-venti): 8- wood hair 

 grass (Deschampsia flexuosa); 9. spine of Can- 

 ada thistle (much enlarged); 10. Canada thistle 

 (Carduus arvensisY 11. stink grass, coryopsis 

 (Eragrostis major) the small figures natural 

 size. 



(After Hicks) 



although it is not unusual 



for only 10 per cent, to germinate. It is necessary in such cases 

 to buy 10 bushels of seed in order to get I bushel of live seed, 

 i Illinois Sta. Bui. No. 15 (1891), p. 481. 



