VITALITY OF THE SEED OF WEEDS. 343 



the last leaf, by a fungus growth. Upon rich land, and where 

 there are few insect larvaj working at the roots, there is little 

 or none of this white top, and we are led to reason that the 

 fungus docs not attack the stem of the grass until the cells 

 have become weakened in some way. 



4. Observatioxs Eegarding the Vitality of the Seed 



OF Various Weeds. 



The several subjects submitted to me for answers by the 

 Board of Control have been carefully investigated, and I am 

 able to make the following report : — 



1 . How is the vitality of the seeds of our most common 

 weeds, such as dock, sorrel, chickweed, shepherd's purse, 

 white daisy, etc., affected by the action of the digestive or- 

 gans of animals? 



A^iswer. Seeds of the dock, sorrel, daisy and shepherd's 

 purse were fed to a horse and the refuse collected. Upon 

 careful examination it was found that the seeds, unless 

 crushed, were uninjured, and germinated readily when placed 

 in soil, under proper conditions of heat and moisture. The 

 experiment was repeated several times with the same result. 



2. How is the vitality of the common weed seeds, like the 

 above, affected by the action of the compost heap? 



Ansiver. Having settled the point that weed seeds are 

 not destroyed by the action of the digestive organs of ani- 

 mals, it becomes important to know how their vitality may 

 be destroyed ; for while the thorough farmer should never 

 allow weeds to mature their seeds on his farm, there are 

 many instances where it becomes necessary to provide some 

 means by which chance seeds may be destroyed, A series 

 of experiments were carried out, the result of which is, that 

 seeds are destroyed if exposed to a temperature of from 90° 

 to 110° F. for from five to seven days in a moist compost 

 heap. In a dry compost heap, where the temperature runs 

 as high as the above, the seeds were found but little injured. 

 The tests were applied only to the above-named seeds ; but 

 it is probable that the results would be the same upon others, 

 as these are among the seeds of the greatest vitality. The 

 efficiency of this mode of destruction depends upon the main- 

 tenance of a continued high temperature and moisture, 



