THE EPIDERMAL SX8TMH. 



cells are so transformed into a secreting organ, 

 tion appears as a rounded 

 pustule, partly surround- 

 ing the secreting cell 

 (Figs. 83 to 87), and 

 which is removed upon 

 the slightest touch. Tri- 

 chomes of this nature are 

 called glandular hairs ; 

 they are exceedingly vari- 

 able in form, and are not 

 infrequently short and 

 depressed, when they are 

 known as surface glands, 

 or glandular scales (Fig. 

 87). 



The secre- 



Glandular hairs from the petiole of 

 o, sinensit, in several stages of deyelop- 



(ft\ Triehomes are in p-ene ment. a, the beginning of the secretion iu the 

 are, in gene- termina , ce]1 . b hair ith a j mags of ge . 



ral, easy objects of study, creted matter ; d, an old hair after the removal 

 In many cases they may be of the secreted matter, x 142.-After De Bary. 



simply scraped off and mounted in alcohol, or in a solution of potash 



FIG. 84. 



FIG. 85. 



FIG. 86. 



FIG. 87. 



Fig. 84. -a', the cell a of Fig. 83 more highly magnified ; a" the same after removal 

 of the secretion by treatment with alcohol, x 87.5. After De Bary. 



Fig. 85 c, end of a hair with large mass of secreted matter ; c', the same after 

 treatment with alcohol, x 375. After De Bary. 



Fig. 8(5. The end of the hair (I, in Fig. 83. more highly magnified, showing the frag- 

 ments of the secretion pustule surrounding the terminal cell, which still contains pro- 

 topjasm X 375 After De Bary. 



Fig. 87. Glandular scale from the hop. A, in its young stage ; B, the same some 

 time afterward the secretion from the cells has pushed out the cuticle and filled the 

 space between it and tho cell* (in the specimen from which these were drawn the 

 secretion was removed by solution in alcohol). X 142. After De Bary. 



after wetting them with alcohol to free them from entangled and en- 

 closed air. 



