T. Holm — Studies in the Cyperacece. 279 



same individual ; the number of pericambium-cells between 

 each two vessels varied in this species from four to seven, but 

 four and five was the commonest. This peculiar case was, 

 moreover, noticed in other specimens from a still higher eleva- 

 tion (2S00 m Mt. Ryssel), in which sometimes most of the 

 proto-hadrome vessels were situated inside the pericambium, 

 and only a very few bordered on endodermis. In C.firma a 

 similar and very irregular position was noticed, since the peri- 

 cambium was either not interrupted at all or it was broken by 

 the majority of the vessels, by 14 out of 15. In C. brachy- 

 stachys we found no case where the pericambium was not 

 interrupted, but the position of the proto-hadrome was very 

 irregular even in the same root, cut at different places. The 

 number of interruptions varied thus between 8 and 13, while 

 the distance between the places where the sections were made 

 was about 5 cm ; in most of the roots of this species, however, 

 we observed that the majority of the proto-hadrome vessels 

 were located inside the pericambium, and only in one root did 

 we notice that fourteen out of nineteen bordered on endoder- 

 mis. In C. ferruginea Scop, we observed that all the proto- 

 hadrome vessels bordered on endodermis in roots of very dif- 

 ferent thickness, but in a single root the following position 

 was noticed : 25 out of 26 vessels had broken through the 

 pericambium, but at the other end of the same root there were 

 only 18 of these 25 vessels that bordered on endodermis.— 

 C. hispidula, C. ferruginea and C. brachystachys illustrate 

 thus the singular fact that the pericambium is very irregularly 

 interrupted by the proto-hadrome, but, on the other hand, 

 we found no cases in these species where it was not inter- 

 rupted at all. C. firma, on the contrary, possesses roots in 

 which the pericambium may sometimes form a closed ring or 

 it may be broken by nearly all the proto-hadrome vessels. This 

 singular instance is, moreover, to be observed in roots of C. 

 supina Wahlbg. in some specimens which we collected in West 

 Greenland ; the species belongs, however, to another section, 

 evidently to the Larnprochlwnoe Drej., which we intend to 

 discuss in a subsequent paper. — But we have not so far noticed 

 auy such variation in any of the other Cyperacece which we 

 have heretofore examined. In regard to the other vessels in 

 the roots of these species we have not found any occupying 

 the center of the central-cylinder, with the exception of small, 

 lateral roots, which usually possessed only one central vessel. 

 The conjunctive tissue which thus occupies the innermost part 

 of the central-cylinder is distinctly thick-walled in all the 

 species, with the exception of C. ablata, where it is thin-walled 

 even in such roots of which the endodermis shows the cell- 

 walls to be very considerably thickened. The leptome, includ- 



