101] XORTH AMERICAN AXD WEST INDIAN CUSCUTA—YUNCKER 11 



studied immediately. The corollas and calyces were split open and 

 mounted on slides in glycerine jelly for study. 



While the European species have been illustrated a number of times, 

 our American forms in many instances have never been pictured. It is 

 believed that the sketches illustrated in the plates will prove of value in 

 making identifications. The types of most of the species treated have 

 been studied and compared. All sketches were made with the aid of an 

 Abbe camera lucida. The drawings were made from what were con- 

 sidered as normal specimens for the species and all details that would be 

 considered as aids for identification are included. It should be remembered 

 that the different species show a variation in their flowers that must be 

 taken into consideration when making comparisons with the drawings. 

 The flowers photographed were selected to show a normal form and possibly 

 supplement the sketches somewhat. The plate illustrating the seeds of 

 some of the different species allows a comparison of their relative shapes 

 and sizes. 



The original publication and the principal monographs treating each 

 species have been cited. Because of the scarcity of good illustrations 

 it was thought best to include citations of practically all known American 

 illustrations. 



