GRASSES OP IOWA. 



181 



become loosened and even drop out, but the animal, impelled by- 

 hunger, still endeavors to eat such hay as may be offered. " 



There are also cases on record where these awns produce 

 hair balls. An interesting account of hair-balls may be found 

 in a paper by Dr. Trelease.* "Barbed trichomes and barbed 



Fig. 75 0. Little barley {Hordeum pusiUum) probably also causes mechanical 

 Injarles. (F. Lamson-Scrlbner Dlv. of Agrost. U. S. Dept. of Agrl.) 



stiff bristles have been known to cause serious injury to stock 

 Professor Coville has recently called attention to some of these 

 coming from a plant that has had considerable advertising as 

 a forage plant, Crimson Clover {Trifolium incarnatum). Pro- 

 fessor Coville t says: "The crimson clover hair-balls, measur- 



•An unusual Phyto-Bezoar. Trans. Acad. Sci. St. Louis. 7; 493. pi. 40. 

 tBot. Gazette. 20: 414. 



