AN EXPERIMENT WITH SEX IN HEMP PLANTS. 



By Byron D. Halsted. 



SIX square boxes two feet upon the four sides and six inches deep 

 were employed, and into one six inches of soil was placed, while 

 a second received five inches, a third four inches, and so on by- 

 regular decrease of depth by one inch until the sixth box was 

 reached that had but a single inch of earth in the bottom. In these 

 boxes hemp seed was sown in equal quantities and in all respects in 

 the same manner, the seed being placed a half inch below the surface. 

 The single difference so far as possible was that of depth of earth as 

 above stated. 



Plants grew in about equal numbers except in box 6, where the 

 earth was only one inch deep and all the seedlings perished. When 

 the plants were in flower the staminate ones were counted with the 

 following result: 



Box r — Earth 6 inches deep ; staminate plants 14 



" " " 20 



' " " " 22 



• <• i< •• 26 



" " 28 



6— " I inch " " " o 



It is seen from this that there was a decided increase in the num- 

 ber of male plants as the depth of soil decreased. It goes without 

 saying that the plants having two inches of earth were smaller than 

 those with six inches — not more than half as high, but the time of 

 coming into bloom was practically the saine. 



This single test accords with the results obtained by M. MoUiard* 

 when he found that under exceptional conditions the ratio between the 

 sexes varied, and the female plants predominated when the conditions 

 were unfavorable for the best growth of the vegetative organs. 



Professor Atkinson in his address f upon "Experimental Mor- 

 phology " states that Hoffman foiind conditions of scanty nutrition 

 had no influence upon the sex of hemp plants, who suggests that the 

 character of the seed is determined during the growth of the seed or 

 by the time of fecundation, whether early or late. 



The various experiments upon the subject indicate that environ- 

 ment is a factor in the determination of the sex in plants, but they do 

 not agree as to the effects. 



*Sur la Determination du Sexe Chez le Chanure— M. Molliard, Comptes Rendus CXXV 

 (1897), pp. 792-4. 



tSection G, Am. Asso Adv. Science, August, 1897. 



Rutgers College, January, 1899. 



