T. Holm — Studies in the CyperaceoB. 211 



In regard to the general habit of these species, C. Davalliana 

 and C. exilis possess a cespitose rhizome, while in the others 

 the rhizome is stolon if erous ; in C. Davalliana var. Sieberiana 

 Opiz, by Fiegert considered as a hybrid between C. dioeca and 

 C. Davalliana, the so-called C. Fiegertii Vollm.,f the rhizome 

 is not so densely cespitose and often bears short stolons. A 

 very slender and stoloniferous rhizome is observable in both 

 the dioecious and monoecious forms of C. gynocrates. The 

 leaves are very narrow in all the species, and the calm is terete 

 and hollow in O. dioeca, C. gynocrates, C. Davalliana, pentag- 

 onal in G. parallela and obtusely triangular in C. exilis. The 

 utricle is usually thickest at the base and tapers gradually 

 into a beak, the orifice of which is cut down on the dorsal face 

 so as to form a slit, but on the ventral side the upper margin 

 is almost entire or slightly emarginate. In C. exilis, however, 

 the beak is bidentate with erect teeth. In the last mentioned 

 species, the utricle is, furthermore, a little winged and the 

 margins are very scabrous, especially above, in which character 

 it differs from the other species of the Dioicce. In C. dioeca 

 and C. exilis the ventral face of utriculus is flat in contrast to 

 the dorsal, which is distinctly convex ; in the other species both 

 faces are convex, and the ventral often prominently so in 

 C. gynocrates. Nerves are quite distinct on the dorsal face of 

 all the species, less so on the ventral, and are very faint in 

 V. dioeca and O. parallela. The base of utriculus is thick 

 and spongy, especially after fecundation has taken place. 



Another peculiarity common to the Dioicce is the change of 

 direction of the utricle when the achenia are mature. While 

 thus utriculus is erect in these species during anthesis, it 

 gradually bends down later on and occupies a horizontal posi- 

 tion in C. gynocrates, 0. Davalliana and 0. exilis, or it 

 becomes merely spreading (suberect) as in C. dioeca and C. 

 parallela. 



The scale-like bracts (squamae) which subtend the pistil- 

 late spikelets are persistent in these species, while they are 

 deciduous in some of the other Monostacliyaz, e. g., C.pidicaris, 

 C. nigricans and C. pyrenaica, in which the utricles show a 

 similar change of direction after fecundation has taken place. 



By possessing several morphological peculiarities in common, 

 the Dioicce may, thus, be considered as naturally allied species. 

 However, we do not feel satisfied with the arrangement of 

 these species as simply representing a section of their own and 

 separated from Vignea and Car ices genuince only on account 

 of their lesser decompound inflorescence and their frequent 

 dicecism. It would seem more natural if these Dioicce could 



* Yollmann, Fr., Ein Beitrag zur Carex-Flora der Umgebung von Regensburg. 

 (Denkschr. d. k. bot. G-esellsch". Regeusburg, vol. vii ; new series, vol. i, 1898.) 



