216 T. Holm — Studies in the Cyperacece. 



quent in the Arctic region and the higher mountains of 

 Norway ; C. Davalliana is a more southern type distributed 

 over Middle Europe and some parts of Asia, Altai for instance ; 

 0. elongata shows a corresponding distribution, but extends a 

 little farther north, at least in Europe ; C. remota accompanies 

 O. elongata, but seems to be more frequent and is, moreover, 

 known from Sikkim Himalaya, where it reaches an elevation 

 of 12,000 feet ;* it is, also, known from Japan. The widest 

 geographical range is, however, exhibited by O. echinata, 

 which is very abundant in Europe and Asia ; besides it is, also, 

 known from North America and New Zealand ; C. sterilis has 

 been reported only from this continent, from Canada to Caro- 

 lina (fide Boott). While thus the dioecious C. parallela and 

 G. dioeca appear to have their center of distribution farther 

 north than any of the others, the monoecious C. gynocrates* 

 although being much less frequent, exhibits a similar range in 

 contrast to its dioecious form, which is more southern. C, 

 exilis represents the most evolute stage of the " hebetataz" and 

 may be considered as a good illustration of the development of 

 the section in this country with its herd of O. echinata and 

 C. sterilis in a number of varieties, of which only the typical 

 C. echinata is distributed in the old world. The nearest allies 

 of C. echinata are, thus, to be sought in this country, where, 

 moreover, C. gynocrates and O. Iceviculmis have their geo- 

 graphical center. C. dioeca and C. parallela are, no doubt, 

 the oldest remnants of the section as this is preserved in recent 

 time, and actually demonstrate a closer affinity to O. exilis 

 than to C. gynocrates and C. Davalliana, even if C. exilis may 

 be considered as younger than any of these. C. elongata and 

 C. remota possess certain points in common with the others,, 

 and may represent the farthest developed types in the section. 

 While thus, considered from a geographical viewpoint, the 

 earlier types belong to the northern parts of the old world, the 

 more modern forms are represented farther south, not only in 

 Europe and Asia, but also in New Zealand and in this country. 

 It might seem strange that the " formge hebetatse " of the sec- 

 tion are so remote from each other as they really are : C* 

 dioeca and C. parallela in Europe and Asia, C. gynocrates in 

 this country, without being connected with each other by some 

 circumpolar type ; yet we must bear in mind that the develop- 

 ment of the section and the migration of the species is not by 

 any means to be fully explained by the present geographical 

 range of a few old types, that are still in existence. 



We have in the preceding pages given a brief account of 

 the morphological characters of the Astrostachyce, and we 



* Clarke, C. B., Cyperacece in Hooker's Flora of British India, vol. vi, London, 

 1894, p. 699. 



