97] NORTH AMERICAN AND WEST INDIAN CUSCUTA—YUNCKER 



INTRODUCTION 



It is now sixty years since the appearance of Engelmanivs monograph 

 of Cuscuta. This paper has served as the basis of our taxonomic knowl- 

 edge of the dodders up to the present. Since Engelmann's time, however, 

 great collections have been made in what was then practically unexplored 

 territory and many new species have been found, a number of which have 

 been described. 



Inspection of the collections in different herbaria shows a great diversity 

 of forms grouped under the same specific name, and the same form often 

 classed under several different species. Also a great number of specimens 

 show no attempt whatever at identification. This confusion is due, to a 

 certain degree, to the fact that many of the distinguishing characters 

 demand a microscopic examination before the species can be identified. 

 This cannot be altered, and the botanist too busy to make dissections will 

 probably never get beyond the guessing stage with many of the species. 

 The different manuals and lists also show considerable confusion in the 

 names applied to the different species and the range accredited to them. 

 In attempting to make certain determinations it was frequently found 

 that the plant in question could easily be called any one of two or three 

 closely allied forms. Pictures had apparently never been made of many 

 of the species. 



It was with the hope of clearing up some of the confusion of nomen- 

 clature and descriptions and also to present the North American and West 

 Indian species in such a manner that they could be recognized clearly 

 that the present work was undertaken. The characters used in the keys 

 have been taken, in so far as practicable, from the exterior of the flower 

 and ordinarily evident under the hand lens. The keys, however, owing 

 to the necessity of employing only floral characteristics, leave much to be 

 desired. 



Fifty-four species are treated in this paper, five of them are introduced, 

 four from Europe and one from South America. Twenty-six species are 

 found in the United States, seven of which are also reported from Canada; 

 thirty-three in Mexico and seven in the West Indies. Of the West Indian 

 species, with the exception of one that enters sparingly from Brazil, all 

 are North American. Fourteen are found both in the United States and 

 Mexico. Of the fifty-four species and forty-two varieties which are 

 accounted for here fourteen species and sixteen varieties are described as 

 new, and of the fifty-four species thirty-two are now figured for the first 

 time. 



