428 T. Holm — Studies in the Cyperacece. 



walled endodermis of the TT-type, and a thin-walled pericam- 

 bium, which is broken by all the proto-hadrorae vessels. The 

 hadrorae consists of several (about eleven) rays of vessels, in 

 which the oldest are mostly single or, but seldom, two side by 

 side. Alternating with these rays are strands of leptome of 

 the usual structure, while the center of the stele is occupied by 

 a broad cylinder of thick-walled conjunctive tissue. In regard 

 to the interruption of the pericambium we noticed in some 

 cases that this is not constant. In the same roots, for instance, 

 a few of the proto-hadrome vessels were located inside this 

 tissue instead of bordering directly on endodermis. Similar 

 variations we have observed and described as characteristic of 

 several other Carices. 



The rhizome. 



The stolons have a moderately thickened epidermis and a 

 broad cortical parenchyma of about twenty layers, containing 

 deposits of starch. Of these the peripheral (six) strata are 

 slightly thick-walled in contrast to the inner ones, which are 

 broken down into wide lacunes. Endodermis shows the same 

 structure as observed in the roots. A pericycle of two to three 

 layers of rather thin-walled stereome surrounds three almost 

 concentric bands of mestome-bundles, of which the peripheral 

 are collateral, the others mostly leptocentric. A thick-walled, 

 starch-bearing pith occupies the center of the stele. 



The culm. 



The flower-bearing stem is sharply triangular, scabrous and 

 solid. The cuticle is smooth and the epidermis shows the 

 outer walls heavily thickened and extended into obtuse papil- 

 lae ; the characteristic cones in the cells of the epidermis were 

 observed outside the stereomatic strands. The cortex contains 

 chlorophyll and consists of six layers of roundish cells (in cross- 

 sections) with rather narrow lacunes but of no palisades. A 

 thick-walled stereome occurs as broad strands on the leptome- 

 and hadrome-side of the mestome-bundles, extending to epi- 

 dermis, besides that an isolated group of this tissue, the stereome, 

 occurs in each of the three angles of the stem. The mestome- 

 strands are arranged in one band, and represent two sizes, 

 smaller and larger ones in regular alternation with each other. 

 They are collateral and possess a thin- walled parenchyma, and 

 a moderately thickened mestome-sheath. The pith is thin- 

 walled, but solid. 



The green leaves. 



The leaves are flat and scabrous, especially on the dorsal 

 face, where the thick-walled epidermis is extended into numer- 



