280 T. Holm — Studies in the Gyperacece. 



ing the proto-leptome, was very well developed in all the species 

 and was located between each two proto-hadrome vessels. 



In examining- the above-ground stem we find that it does 

 not exhibit such striking divergences as was noticed in the 

 roots. Sections taken from about the middle part of the culm 

 showed the outline to vary from cylindrical to sharply triangu- 

 lar as follows : it was found to be terete and nearly glabrous in - 

 G. circinata, G sempervirens and G. brachystachys ; pentago- 

 nal and almost glabrous in G. ferruginea ; obtusely triangular 

 and glabrous in G. ablata ; triangular and nearly glabrous in 

 C. Itjocarpa, G. misandra and G. frigida, while triangular 

 and very scabrous in G. firma and G. hispidula. The cuticle 

 is quite thick and perfectly smooth, not wrinkled in these 

 species. The epidermis shows generally a distinct thickening 

 of the outer wall, especially in C. sempervirens and C. ablata / 

 the radial cell-walls are a little thickened in G. ferruginea, G. 

 frigida and G. ablata. Cone-cells were found outside the 

 hypodermal stereome in all species ; stomata occurred fre- 

 quently in that part of epidermis which covered the bark and 

 showed the same structure as in the leaves, which will be 

 described later. A somewhat peculiar epidermal structure is 

 represented by G. hispidula, where the outer wall in nearly all 

 the cells was noticed to be extended into roundish papillae, 

 especially near the stomata, although not covering these. The 

 cortical parenchyma is mostly developed as short palisades, 

 radiating towards the center of the stem, and contains lacunes, 

 sometimes of quite considerable width in G. circinata, G. lejo- 

 carpa and G. hispidxda. The stereome occurs as hypodermal 

 groups, covering the larger mestome-bundles, but is also to be 

 found on the hadrome side of these, bordering on the pith. The 

 smaller mestome-bundles have usually only a minute support of 

 stereome, this being merely developed as a few cells on either 

 face of these. This tissue, the stereome, is very thick-walled, 

 at least on the leptome-side, in G. circinata, G. sempervirens, 

 G. hispidula, G. fir-ma, G. frigida and G. brachystachys, 

 much less so in the remaining species, and it is generally rather 

 open on the hadrome-side of all the mestome-bundles. 



The mestome-bundles are developed as larger, in transverse 

 sections oval, or as smaller, nearly orbicular, and are arranged 

 in almost regular alternation with each other. They constitute 

 in most of the species only one peripheral band, but in G. his- 

 pidula, G. ablata and G. brachystachys we noticed an inner 

 band of a few, 3 to 5, large bundles, almost entirely imbedded 

 in the pith. The parenchyma-sheath is invariably thin- walled 

 and seems often to contain chlorophyll ; a mestome-sheath with 

 the inner walls distinctly thickened is also noticeable in all the 



