T. Holm — Studies in the Cyperacece. 177 



position of the stems in proportion to the light, and by com- 

 paring leaves of various genera no apparent connection seems 

 to exist between their presence and the shape or direction of 

 the leaf-blades. The genus Fimbristylis, for instance, on 

 which the writer has prepared an article for this Journal, 

 exhibits a most remarkable variation of growth as regards stem 

 and leaf, yet invariably possessing the same arrangement of the 

 palisade-cells and development of the inner chlorophyll-bearing 

 sheath. 



Whether the radial arrangement of the palisade-cells around 

 the mestome-bundles is beneficial to the plant, is a question that 

 cannot be settled at present. It is, also, very uncertain whether 

 the dark, green chlorophyll of the inner sheath possesses a 

 higher assimilating power than that surrounding ; very diverse 

 opinions have been expressed regarding these questions, and a 

 brief summary may be found in the work of Warming, cited 

 above. 



In returning to the stem-structure of Lipocarpha, the 

 leptome and hadrome have attained their highest development 

 in the inner mestome-bundles, but are not, in any of the species 

 we have examined, separated from each other by thick-walled 

 mestome-parenchyma, as described by Kikli (Z. argentea). 

 There is, furthermore, a large, solid pith w r hich is composed of 

 thin-walled cells, hexagonal in transverse section, in Z. sphace- 

 lata and Z. maculata ; in L. argentea and Z. microcephala, on 

 the other hand, we noticed the pith to be interrupted by large 

 and apparently very irregular lacunes. Cells containing tannin 

 were observed in the pith, close to the mestome-bundles. 



Very different is the structure of rhachis, that part of the 

 stem which bears the spikelets. The bark-parenchyma con- 

 tains no chlorophyll and forms a broad ring around the cen- 

 tral-cylinder ; the mestome-bundles are mostly small and 

 surrounded by a typical, colorless parenchyma sheath and a 

 thin- walled mestome-sheath, while the inner sheath is totally 

 absent. The arrangement of the mestome-bundles is, also, dif- 

 ferent, there being a closed band near the center of the axis, 

 while a few are seen to be scattered towards the periphery, 

 entering the rhacheolae of the spikelets. The rhachis seems 

 totally destitute of stereome and the solid pith occupies only a 

 small part of the central-cylinder. Furthermore we observed 

 that tannin was present in some of the pith-cells as well as in 

 the bark-parenchyma. 



The leaf. 

 The stem-leaves of the species of Zipocarpka, which have 

 been examined, are rather weak, with narrowly linear blades, 

 closed tubular sheaths, but no ligule. The margins of the 



