EXERCISE 18 (Continued) 



FIG. 37. A weed seed holder. This device can be made from two layers of thick cardboard by means 



of a shotgun wad cutter. 



References. Montgomery, E. G. 1916 Productive Farm Crops (Lip- 



PINCOTT), Chap. XXXV. Ward, H. M., 1908, Grasses (Cambridge University 



Press). Testing Farm Seeds in the Home and Rural School, U. S. D. A. 



Farmers' Bui. 428. Hitchcock, A. S., 1914, Text-book of Grasses (Macmillan). 



60 



