444 



T. Holm, — Studies in the Cyperacece. 



Besides being surrounded by the radially arranged palisade - 

 cells, the mestome-bundles possess, also, a completely closed 

 parenchyma-sheath of small, thin-walled cells, which contain 

 chlorophyll. Inside of this parenchyma-sheath there is a 

 mestome-sheath, thin- walled in F autumnalis and F. thermalis, 

 but more or less thickened in the other species. The peculiar 

 " inner chlorophyll-bearing sheath," which we described in a 

 previous article upon Lipoearpha* occurs, also, in Fimbris- 

 tylis, and not only in the genus " sensu strictiori," but also in 

 those American species of Isolepis which we have included in 

 the former genus. We found the structure of this sheath to 

 be identical with that of Zipocarpha, being composed of much 

 larger cells than the mestome-sheath ; also by being closed in 

 the small, orbicular bundles, but interrupted in the larger 



(iig. 10). The cell-content seems, 

 also, to present the same deep 

 green color as noticeable in Zipo- 

 carpha. 



As regards the hadrome and lep- 

 tome these have, naturally, attained 

 their highest degree of develop- 

 ment in the largest mestome- 

 bundles, where these tissues are 

 sometimes separated from each 

 other by one or more layers of 

 thick-walled mestome-parench} 7 ma, 

 as in F. castan ea, F. puberula, F. 

 spadieea and F. complanata. The 

 presence of the inner, chlorophyll- 

 bearing sheath in our species of 

 FimbristyUs will necessarily place 

 the genus as a member of Rikli's 

 " Chlorocyperacece" among which 

 this author has not, however, 

 enumerated any of the Isolepis- 

 species examined by him. More- 

 over the morphological and ana- 

 tomical diagnosis of Isolepis, as demonstrated by Palla, does 

 not seem comparable with any of the North American plants 

 which by Torrey were referred to this genus. Our species 

 differ very much from Isolepis proper by their morphological 

 characters, also by their internal structure. And even if the 

 inner, green sheath is not a constant character to all species in 

 certain large genera such as Heleocharis and Cyperus, as dem- 

 onstrated by Rikli, it would not be correct to consider our 



Fig. 10. Transverse section of 

 a mestome-bundle from the leaf of 

 F. autumnalis ; Ep. = epidermis of 

 the upper surface, x 400. 



*This Journal, vol. vii, p. 172. 



