T. Holm — Studies in the Cyperacece. 45 



lated group in each of the two margins. The mestome- 

 bundles are arranged in one plane, larger alternating with 

 smaller ones ; the parenchyma-sheath is thin-walled and color- 

 less ; the mestome-sheath shows distinctly thickened inner cell- 

 walls. The bracts, which subtend the one-flowered, female 

 spiculae in C. Steudelii, C. Backii and O. Willdenowii are 

 leaf-like, at least the lower ones, and show a structure corre- 

 sponding to that of the proper leaves, only that they are rela- 

 tively narrower and possess more stereome than these. The 

 bracts of the uppermost female spikelets are, on the contrary, 

 scale-like, awned, membranaceous and with hyaline margins 

 like the scales of the Hymenochlcence in general. 



In comparing the leaf of C. Stendelii, C. Backii and C. 

 Willdenowii with that of C. wdipostyla we notice almost the 

 same structure ; but the outer wall of epidermis is thicker in 

 this species, and without any development of papillae, as we 

 noticed in C. Backii for instance; the mesophyll is very open 

 and is not differentiated into any distinct palisade-tissue. The 

 stereome is quite thick-walled, and the mestome-sheath has its 

 inner cell-walls considerably more thickened than we observed 

 in the former species. The leaves of C. Geyeri and 0. multi- 

 caulis are longer and much narrower than in any of the former 

 species; they are slightly conduplicate with a distinct keel in 

 the former, but in the latter the midrib is not projecting. The 

 outer cell-wall of epidermis is quite thick, especially so in the 

 bulliform cells, which are here relatively small and occur as a 

 single group above the midrib, when viewed in transverse sec- 

 tions. No papillae are visible around the stomata, but in C. 

 multicaulis there are a few rows of such projections on each 

 side of the bulliform cells, similar to those observed in C. 

 Backii. The stomata are level with epidermis and confined to 

 the lower surface of the blade. The mesophyll is a dense 

 palisade-tissue with a lacnne between each two mestome-bundles 

 in C. Geyeri, but is more open in the other species. The 

 stereome is extremely thick-walled in both species and accom- 

 panies the mestome-bundles, besides that it, also, occurs as 

 isolated groups in each of the two margins in C. midticaidis, 

 but not in C. Geyeri. The mestome-bundles themselves show 

 the same structure as we have found in the other species, 

 described above, but the mestome-sheath is more thick-walled 

 than in these. 



Utriculus. 



This little organ furnishes the most essential characters in 

 distinguishing the sections and even the species of Carex. It 

 is almost bottle-shaped in C. Steudelii with a long, straight and 

 rough beak, and is readily distinguished from that of C. Willder 



