DESCRIPTION OF PLATES. 



Plate I. Fig. 1. — Bromus rnceniosua, smooth hrome grass. Fig. 2. — Bromus secalinus, 

 cheat or chess. The two divisions at the right of each figure show the vigorous 

 growth made ])y the clieck samples. In the three divisions at the left, A, B, and 

 C, were planted the seeds which had heen buried at depths of 6 to 8 inches," 18 

 to 22 inches, and 36 to 42 inches, respectively. The vitality of the seeds of these 

 two species, which are considered as noxious weeds in the grain fields of the 

 United States, was destroyed at the expiration of eleven months. 



Plate II. Fig. 1. — Alsine media, common chickweed. Fig. 2. — Rume.i: crispiis, curled 

 dock. Fig. 3. — Datura tatula, jimson weed. Seedlings from weed seeds which 

 did not lose their vitality by Inirial for eleven months, as shown in the three 

 divisions at the left of each flat, the germination being practically the same as 

 in the case of the two check samples shown at the right of each flat. 



Plate III. Fig. l.—Elymus canadensis, nodding wild rye. A, buried 6 to 8 inches — 

 all killed; B, buried 18 to 22 inches — only one seedling shows in the figure, but 

 the total germination was 7 per cent, as given in the table; C, buried 36 to 42 

 inches— germinated 22 per cent; the two check samples at the right made vigor- 

 ous growth, germinating 81 percent. Fig. 2. — Fraxinus ameriadius, white ash. 

 A, buried 6 to 8 inches, and B, buried 18 to 22 inches — all killed; C, buried 

 36 to 42 inches — germinated 84 per cent; the check samples germinated 26 per 

 cent, but the seedlings had "damped off" before the photograph was taken. 

 Fig. 3.^F]iytoIacca americana, poke. A, buried 6 to 8 inchea — germinated 7.5 

 percent; B, buried 18 to 22 inches — germinated 60.5 per cent; C, l)uried 36 to 

 42 inches — germinated 80.5 per cent; the two check samples germinated 84.5 per 

 cent. 



The illustrations show that in many cases the vitality of seeds is better preserved 

 at a depth of 36 to 42 inches than at shallower depths. 

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