A Monograph of the North American species of 

 Rhynchospora. By Asa Gray, M. D. 



Read December, 1834. 



The natural order Cyperace^ has, in proportion to the 

 number of species it comprises, been less carefully studied than 

 any other family of phenogamous plants. Notwithstanding the 

 researches of R. Brown, Kunth, Nees von Esenbeck, &c. 

 who have illustrated particular portions of this family, the distinc- 

 tive characters of the genera are, in many cases, highly unsatis- 

 factory, and the determination of species is frequently difficult. 

 The whole order requires an elaborate revision by some com- 

 petent person, who can consult the principal herbaria of pre- 

 ceding botanists, as well as many important works, which, from 

 their great cost or extreme scarcity, are inaccessible to us. — 

 But the plants of any single country may be most advanta- 

 geously studied by a botanist who is familiar with them in their 

 native situations, and who has opportunides of examining and 

 comparing with each other numerous specimens from various 

 localities. 



A person who in this way confines his attention, for a time 

 at least, to the critical examination of a single genus or family 

 of plants, and who carefully records the facts which he ob- 

 serves, may furnish important materials to those who, with 

 more ample means, are to succeed him in the same field ; and 

 thus contribute, in some degree, to the advancement of the 

 cause of science. 



The follow^ing account of the North American species of 

 Rhynchospora has been prepared under circumstances highly 

 favourable for arriving at correct results. With a liberality 

 which does honour to the cause in which they are engaged, my 

 botanical friends have placed their collections at my disposal 



Vol. III. 25 



