Nuith American Cyperaccie. 243 



In arranging the Cyperacea3 described in tlie lollovving pages, 

 I have adopted the classification of Nees ab Esenbeck, as given 

 in the 9th volume of the Linngea already quoted, without, 

 however, agreeing with the learned author in all his views, par- 

 ticularly in the extent to which he has divided some of the older 

 genera. The characters of his tribes and genera are so brief, 

 that I have thought it expedient to enlarge, and in many cases 

 to modify them materially. In framing the diagnoses of the 

 species, it may be thought by some botanists that I have employ- 

 ed characters which are too microscopic, but this course was 

 absolutely necessary, since the most certain marks of discrimina- 

 tion in this family exist in the minute and highly organized parts 

 of fructification, which until lately have been very little regarded 

 by botanical w^riters. The form, texture, relative size, posi- 

 tion, &c. of the scales, perianth, nut, and style, afford charac- 

 ters on which we can place the most reliance in the Cyperaceae. 

 The accompanying table exhibits a view of the North Ameri- 

 can genera of this family, arranged according to the Synopsis of 

 Nees ab Esenbeck, with the number of species belonging to each 

 genus, and the proportion which the endemic species bear to 

 those which also inhabit Europe, or other parts of the world. 



Of the Tribe Cypereae the greatest proportion belong to the 

 Southern States. The genus Cyperus itself scarcely extends 

 into Canada, and in all New England not more than 7 or 8 species 

 have been found. Proceeding south they become more frequent, 

 and the maximum is attained in the regions bordering the Gulf 

 of Mexico. Kyllingia does not occur north of Pennsylvania. 

 Mariscus is found throughout the United States, andDulichium, 

 a doubtful member of this tribe, has an equally extensive range. 

 Hypolytreae constitute a small tribe. Lipocarpha is pecu- 

 liarly southern, andFuirena is rarely found as far north as Bos- 

 ton ; and, in the northern and middle states, only in the vicinity 

 of the ocean. 



Scirpese are widely distributed, but at least two thirds of the 

 species occur south of Virginia. Abildgaardia and Elytrosper- 

 mum have only been observed on the Pacific coast of America. 

 The genuine species of Scirpus range from the Arctic regions 

 to Florida, and from the Atlantic to the Pacific ; and Eleocharis 



