244 Nurlh Aiiicrican Cijjjeraeecr. 



has a similar range. Eriopliorum is a northern genus, 

 only one of its species extending beyond Pennsylvania. 

 Chcetocyperus is peculiar to the south. Fimbristylis does not 

 reach the northern limits of the United States. Isolepis is 

 chiefly southern. Our solitary species of Trichelostylis occurs 

 in nearly all parts of North America south of Canada. 



Rhynchosporeae are, with few exceptions, southern plants. 

 Dichromena is not found north of Virginia nor far from the 

 ocean. Two Psilocaryce are southern, and a third has been 

 observed only in Massachusetts. Of the 28 species of Rhyn- 

 chospora but four are found as far north as Boston, and only 

 eight belong to the middle states ; the remainder are mostly 

 peculiar to the southern states, but many of them extend west 

 to Texas. Of the two species of Ceratoschcenus, one inhabits 

 a large part of the United States south of Delaware and west 

 to the Mississippi ; the other is found only in New England. 



The tribe Cladiese is represented by two species of the 

 genus Cladium, one of which is northern, the other southern. 



Of Scleriege we have but two genera and eleven species, two 

 or three of which have an extensive range in latitude and longi- 

 tude, but most of them are southern and are confined to the 

 vicinity of the ocean. 



A solitary species of the small tribe Elynece inhabits the 

 boreal regions of the continent. 



The vast genus Carex, which almost exclusively constitutes 

 the tribe Caricese, predominates in the northern parts of the 

 continent, and many of its species are peculiar to the boreal 

 and arctic regions ; but a large number inhabit almost every part 

 of North America. Of Unciniawe have but a single species, a 

 native of British America. 



It remains for me to state the sources from whence I obtain- 

 ed a large portion of the materials used in the preparation of 

 this monograph. 



To my much valued friend Sir William J. Hooker I am 

 greatly indebted, not only for free access to his unrivalled her- 

 barium, but for a liberal supply of specimens from the collec- 

 tions made by Dr. Richardson, T. Drummond and other travel- 



