220 T. Holm — Studies in the Cyperacece. 



in C. remota we find the leaves to be almost flat with a distinct, 

 keel as is characteristic of the majority of the higher developed 

 Vignem and Carices genuine®. In the " hebetatse " the leaves 

 are smooth and mostly glabrous, with the exception of C. 

 Davalliana ; in the others, " centrales and desciscentes," we 

 find prickle-like projections to be quite abundant along the 

 margins and the midrib, rendering the leaves more or less 

 scabrous. Very characteristic in this respect is the leaf of 



Fig. 2. Carex gynocrates Wormskj.; monoecious specimen from Wyoming; 

 transverse section of leaf ; mesophy 11 painted black ; M.=midrib; E. = epidermis 

 of upper face, x 120. 



C. Iceviculmis (fig. 4), of which both surfaces show the develop- 

 ment of a number of obtuse papillae. The cuticle is very 

 distinct and smooth in all the species, and the epidermis shows 

 relatively the same modifications as seen in most of the other 

 Carices: the cells being generally larger on the upper face 

 outside the mesophyll than on the lower. Bulliform cells are 

 well developed as a single group above the midrib in all the 

 central forms and in 0. remota, besides that an additional 

 group of these may be seen in C. remota (fig. 3) above one of 

 the lateral mestome-bundles. The "hebetatse" are mostly 

 destitute of these bulliform cells, and it is only in the broader 

 leaves of C. parallela (male specimens) and of C. Davalliana 

 that some of the epidermal cells have attained such develop- 

 ment, although in a much smaller degree than in the " formse 

 centrales." If we consider epidermis of the lower surface and 

 outside the stereome, we notice the cells to be of a somewhat 

 different size and shape than in the surrounding stomatiferous 

 strata; the radial walls are less undulate and the cells often 

 shorter and narrower than those adjoining. In C. parallela 

 and in O. exilis, for instance, these epidermal cells outside the 

 stereome are shorter than the others ; in G. Davalliana, 0. 

 sterilise O. remota and C. Iceviculmis they are much narrower. 



