38 



HEREDITY AS ILLUSTRATED BY TRICHOMES. 



Fig. 9. Trichomes otJuglans californica nigra, Fy. a, awn-shaped trichome from a leaf; b to <l, 

 disk-shaped trichomes ; e to i, some stages in the development of long secreting trichomes : 

 ,/', transverse section of head of mature long secreting trichome ; A' to m, long secreting tri- 

 chomes; n to r, long secreting trichomes of the type having a head of more than t cells; 

 n, longitudinal sections of the head of a single trichome; o to q, views of long secreting tri- 

 chomes ; r, transverse sections of head of long secreting trichomes of different ages ; s, some 

 stages inUhe development of short secreting trichomes. (All figures 585; reduced one- 

 fourth.) 



