ELEMENTA.IIT STRUCTTTKE. 



49 



style, and the stigma of Flowering Plants are also covered by a 

 modified epidermis, resembling epiblema in its general characters, 

 to which the name of Epithelium has been given by Schleiden. 



b. Cuticle. — This consists generally of a thin transparent pellicle, 

 which covers the entire surfiice 



of the epidermal cells (figs. 98, a. Fig. 1 00. 



and 100), with the exception 

 of the openings called stomata. 

 It forms a sheath also over the 

 hairs {fig. 100). The cuticle 

 has no cellular structure, or in- 

 deed any evident organization, Fig.lOO. Cuticle of the Cabhage.showiug 

 although in certain cases it pre- ^}^^^ '•^'f perforated l.y the stomata, and 



^ ^ , , ^ forms sheaths over the hairs, 



sents a somewhat granular ap- 

 pearance, and is marked by lines formed evidently by the epidermal 

 cells with which it was in contact. It is frequently prolonged into the 

 openings of the stomata, and from thence into the passages which 

 commonly exist between the sides of the cells below the epidermis 



Fig. 101. 



Fig. 102. 



Fig. 103. 



Fig. 101. Cistome from Cereus peruvianus. After Gasparrini. Fig. 102. 



Cistomes of Ornithogalum nutans, ramifying in the intercellular passages 

 beneath the epidermis. After Gasparrini. 



(%. 102), and may then be separated by boiling in nitric acid as 

 a somewhat funnel-shaped bag (fig. 101). To this prolongation 

 of the cuticle, which Gasparrini first 

 described, and which he wrongly re- 

 garded as a peculiar organ, he gave 

 the name of Cistorne. 



In rare cases, the cuticle, which 

 is generally a very thin pellicle, be- 

 comes of considerable thickness, as 

 in the upper surface of the leaves 



of Cycas, (fig. 103). The nature J^ifi'. los. sectim of a leaf of (7j/ca« 

 of cuticle has given rise to much ^Sfd' g7lhfc?ene'd''2Sl a', 

 discussion, and cannot be said to be After schieiden. 

 as yet accurately determined. By most observers it is regarded 

 as an excretion from the epidermal cells, which has become 



