MALE AND FEMALE FLOWERS OF HEMP 

 Figure 18. Pendent stamens can be seen in some of the male flowers (left), while the protrud- 

 ing stigmas are \'isible in nearly all of the female flowers. 



The dioecism of hemp greatly' simplifies the technique of experimental pollination, as it elim- 

 inates the necessity of emasculating the flowers. It is more difficult to establish genetically pure 

 strains of a dioecious plant than of one that can be self-fertilized, and it is impossible to establish 

 a pure line in the strict sense of the term. 



fruited at about the same time. 

 Seed sown during the fall and winter 

 months produced shorter and more 

 slender plants that fruited in a much 

 less time than the summer plantings. 

 Plants from seed sown in August, and 

 those from seed sown in December both 

 fruited in March. 



These observations illustrate in a 

 general way the influence of environ- 

 mental conditions upon the growth of 

 hemp. The lack of critical tests is 

 recognized by the writer but the differ- 

 ences were very striking and were no- 

 ticed at once by casual visitors not 

 engaged in scientific investigations. 

 The relationship between size of plant 

 and size of jar is not of universal 

 occurrence and is of considerable 

 interest from this standpoint. While 



most plants show some reaction to 

 the amount of space available for 

 root development, they do not all 

 respond so distinctly as hemp. This 

 relationship would enable us to control 

 the size of plant desired by regulating 

 the amount of root space available. 

 The plants in the greenhouse were 

 easily grown, thrifty, vigorous, and 

 free from destructive disease and insect 

 enemies. 



The dioecious nature of hemp is of 

 considerable advantage in that it 

 eliminates the labor involved in emas- 

 culation. This manipulation requires 

 considerable time in certain plants 

 like barley, but demands relatively 

 little effort in other forms such as 

 tobacco. In working with a dioecious 

 plant one is at a disadvantage in 



