Lloyd : Anatomy of Chrysoma pauciflsoculosa 



447 



cessory cells lying adjacent, the presence of which in the Corn^ 

 positae is, so far as known, of rather rare occurrence, according 

 to Benecke.* These cells are not, however, as well differentiated 

 as in Carlina (Benecke, /. c), but nevertheless serve to raise the 

 stoma somewhat above the level of the epidermis, and, by the con- 

 formation of their walls, to aid in closing the aperture. 



The stomata are to be found only in the "pellucid " areas, from 

 the margins of which they are absent. In each area there are, on 

 an average, about 22. They are found also upon the rounded 

 edges of the leaf. The average size of the areas is 0.19 sq. mm. 

 The stomata are therefore relatively numerous in the areas in which 

 they occur. 



Fig. 3a y Double glandular hair; 3/;, older condition, with collapsed cells; 4, 

 single glandular hair ; 5, whip hair. 



The exposed surface of the leaf is entirely smooth and free 

 from organs such as hairs. The cuticle is sculptured into irregular 

 ndges, chiefly over the veins, and inconstantly over the rest of the 

 surface. Two kinds of hairs grow in abundance at the bottoms of 

 the sulci. Of these, one sort is glandular, the other, the so-called 

 whip cells, f 



The former are composed of two series of four cells each, the 

 basal cells being the smallest (Fig. 3a). Their walls are thin and 

 have a delicate cuticularized external layer. In the terminal cell one 

 always finds a rounded mass of calcium oxalate crystals. In the 

 mature leaf the three lower cells appear empty and are collapsed 



Vii 



* Bot. Zeit. 1892. 



t Vesque, J., Caract6res des * * * gamopetales 



- 1 : 183. 1885. 



* # * 



Ann. Sci. Nat. Bot 



