208 T. Holm — Studies in the Cyperacem. 



Boott* says of C. exilis : " The existence of these distinct 

 spicule necessarily separate the species from the Psyllophorce. 

 It proves the correctness of the remark of Drejer, that that 

 artificial group is to be considered as "formse hebetatse Cari- 

 cum ; monostachyse incipiunt, evaduntque pliostachyee. The 

 evident affinity of C. exilis is with the Stellulatce ....;" a 

 similar suggestion was also made by Tuckermann, as men- 

 tioned above. 



In looking over the Vignem and Cariees genuinm mono- 

 stachyous specimens are sometimes met with, especially among 

 the latter, but such forms are hardly to be considered as typ- 

 ical, even if they may be quite common, for instance C. 

 typhina and C. squarrosa, both of which abound in the 

 vicinity of Washington, D. C, with a single gynsecandrous 

 spike, subtended by several leaf-like bracts, indicating the sup- 

 pression of the lateral spikes ; these forms have, also, been 

 found in many other places in the eastern United States, and 

 seem to predominate, the typical pliostachyous forms being 

 much less common in certain regions. It thus appears as if 

 the Psyllophorce in general exhibit some characters by which 

 they may be distinguished from the other Cariees : " spica 

 unica simplicissima androgyna sive dioica," as indicated by 

 Tuckermann, but beyond this distinction most of the species 

 are readily noticed to be inseparable from Vignem or Cariees 

 genuince. This becomes the more evident when we consider 

 the structure of utriculus, which furnishes such excellent char- 

 acters for distinguishing the species and even the "greges," 

 and is of much greater importance than those characters, 

 which are derived from the less decompound inflorescence, 

 the number of stigmata and the separation of the sexes in 

 some of the species. When speaking of utriculus, we must 

 admit, however, that this exhibits a peculiarity which seems 

 characteristic of a number of Psyllophorce in contrast to the 

 Vignem and Cariees genuince in general ; and is evidently a 

 sign of lesser development. This is to be noticed in the ori- 

 fice of utriculus, which is unequally slit in the Dioiem ; thus 

 •the upper margin is almost entire on the ventral face, but cut 

 down more or less deeply on the dorsal, the convex face. In 

 the higher developed forms, Vignece and Cariees genuinm, the 

 beak is mostly bidentate or cut down equally on both faces, 

 especially so in the latter. But this character, the unequally 

 slit orifice of utriculus, is not peculiar to all the Psyllophorce 

 and is, moreover, to be observed in some of the Cariees 

 genuinm, as pointed out by Drejer. But otherwise the utricle 

 does not show any difference of importance, by which the 

 Psyllophorce may be distinguished from the other Cariees, 



* Ibidem, p. 17. 



