

T. Holm — Studies in the Cyperacece. 



441 



erally applied. A structure similar to that of F. jmoerula but 

 without hairs is to be found in F. thermalis (fig. 5), of which 

 the writer received some excellent material from Dr. E. L. 

 Greene. The leaf-blade is here broad and very thick from the 

 immense layers of colorless tissue on the upper surface, the 

 function of which cannot possibly be for the storage of w T ater, 

 since the specimens were growing in hot sulphur springs. F. 

 castanea exhibits a very peculiar shape of leaf, this being semi- 

 cylindrical (fig. 6), and of which the upper surface shows a 



Fig. 5. Transverse section of half of the leaf-blade of F. thermalis. x 15. 



still larger development of colorless tissue than any of the 

 other species we have examined. It was rather surprising to 

 find this narrow leaf developed on a species that inhabits 

 brackish marshes, which are not liable to become dried out 

 during the summer. It is actually the narrowest leaf we 

 have observed in any of the 

 North American species of 

 Fimbristylis, in proportion 

 to its length, and the only 

 species that possess approxi- 

 mately as narrow leaves are 

 just those which inhabit a 

 very dry and sandy soii : 

 F. capillaris, F. ciliatifolia, 

 F. Warei and F. stenophylla. 

 The accompanying figures 

 (figs. 7, 8 and 9) illustrate 

 transverse sections of leaves 



from the latter three species, Fig. 6. Transverse section of leaf-blade 



and we notice at once the of F - castanea. x 75. 

 very narrow, almost triangular outline from the strongly pro- 

 jecting midrib. No large tissue for water-storage is developed 

 in any of these species, but the cells of epidermis are on both 

 surfaces relatively wide, and sometimes a double epidermis 

 may be developed between the mestome-bundles, in both F. 

 ciliatifolia and F. Warei. Characteristic of the leaf of F. 



