T. Holm — Studies In the Cyperacece. 423 



The root-structure shows nothing of particular interest, but 

 we might mention that a hypoderm is developed, and that the 

 cortical parenchyma is divided into two distinct zones, a peri- 

 pheral of three to five layers, which are thick-walled, and an in- 

 ner of about ten strata, thin- walled and tangentially collapsed. 

 Furthermore that the pericambium is interrupted by all (six) 

 the proto-hadrome vessels. 



The flower-bearing stem is cylindric, furrowed, but glabrous. 

 Very peculiar is the structure of epidermis/" The outer, and 

 partially also the lateral, cell-walls show an enormous thicken- 

 ing and are extended into large, club-shaped papillae around 

 the stomata, which are sunk below the adjoining epidermis 

 (fig. 1). Where epidermis covers the stereome, the cell-walls 

 are, also, very thick but not extended into papillae. The cor- 

 tical parenchyma is developed as palisades radiating towards 

 the center of the stem, except those that border on the mestome- 

 strands, which radiate toward the center of these. The mes- 

 tome-strands are located in one circular band, large and small 

 in regular alternation with each other. Of these the former, 

 the larger ones, have a support of stereome extending to the 

 epidermis. A thin-walled parenchyma- and a thick-walled 

 mestome-sheath surrounds each mestome-bundle. The pith 

 is thin-walled and hollow ; thus we have in this species of 

 Carex a cylindric and hollow stem ; we remember that a trian- 

 gular and solid stem is the most frequent in the Cyperacece. 



The leaves are very narrow, but flat, at least toward the base ; 

 near the apex they are hemicylindric with a groove in the 

 middle. "We find here the same thick-walled epidermis as 

 observed in the stem, and the stomata are, also, here surrounded 

 by protuberances of the outer cell-walls. These protuberances 

 (fig. 2) show a very peculiar shape, being branched at the sum- 

 mit, a structure which we have not, so far, observed in any 

 other " forma hebetata" of Carex. The lumen of the epider- 

 mis is somewhat wider on the ventral face than on the lower, 

 but bulliform cells in the stricter sense of the word are not 

 developed. The chlorenchyma consists of palisades arranged 

 in the same way as in the stem, but is interrupted by wide 

 lacunes. The stereome is very thick-walled and accompanies 

 the larger mestome-bundles as hypodermal strands. There are 

 about nine mestome-bundles, of which the three are much 

 larger than the others ; each is surrounded by a thin-walled 

 parenchyma- and a thick-walled mestome-sheath. 



The perigynium. 



The very thin perigynium is glabrous except near the apex, 

 where a few prickle-like projections are to be observed. The 

 * Compare this Journal, vol. x, p. 282, 1900. 



