8 T. Holm — Studies in the Cyperacece. 



Some other divergencies may be observed in the relative 

 development of the bark-parenchyma and the stereome of the 

 stem ; we notice, for instance, a very thin bark-parenchyma in 

 S. oligantha, in contrast to S. filiformis and S. ciliata, where 

 the same tissue forms strata of rather large dimensions. The 

 stereome seems to be present in larger groups and to be more 

 thick-walled in S. pauciflora, S. Baldwini and S. ciliata than 

 in any of the other species. The pith is broken by lacunes in 

 S. Torreyana, S. reticularis and S. filiforrnis, but is solid in 

 the other species. 



The leaf. 



The leaves of our species are provided with a tubular sheath 

 and a long linear blade, which is very narrow in the North 

 American species with the exception of S. triglomerata. Scleria 

 is marked by the total absence of a ligula. Projections from 

 the epidermis, such as spines or warts, are scarce, and S. tri- 

 glomerata seems to be the only one of our species in which 

 continuous rows of rather sharp and curved projections are 

 visible above the stronger ribs in the leaf-blade. Hairs are, on 

 the other hand, common, and occur as a more or less dense 

 pubescence upon the sheaths of all our species, or as scattered, 

 soft hairs along the margins of the leaf-blade, besides and not 

 infrequently upon the upper face of the blade, covering the 

 furrows between the stronger ribs. 



The anatomical structure of the leaf-blade seems to be veiy 

 uniform in our species, yet exhibits some peculiarities which 

 enable us to separate the species, at least in groups by anatom- 

 ical characters. In Scleria pauciflora the stomata are confined 

 to the lower face of the leaf- blade, forming longitudinal rows 

 underneath the mesophyll. The cells of epidermis are rather 



Fig. 2. Leaf of S. pauciflora ; transverse section ; B C, the bulliform cells. 

 xl20. 



large and thin-walled on both faces of the blade, and form a 

 single group of the characteristic bulliform cells above the 

 midrib (B C in fig. 2). The other cells of epidermis of the 

 upper face are remarkably large, but without attaining the 



