REVISIOM 



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North American Uml)ellifer3e. 



The Order UiHbcUifcrt.c has always been considered a most 

 perplexing one, chiefly because tl.e characters ordinarilv used 

 among flowering plants are of no avail, and the attempt to use 

 them has led to confusion. The order must still be considered a 

 difficult one to the ordininy stut'.ent, inasmuch as it demands care- 

 ful sections of the fruit anil an examination of rather minute struct- 

 ures. 



In our revision of the North American species we arc much 

 indebted to the hearty co-operation of botanists and desire to make 

 the following acknowledgements: To our lamented leader. Dr. 

 Asa Gray, the inception of tiie work was due, and his c<<nstant 

 encouragement at first made the final loss of it doublv felt. Dr. 

 Sereno Watson has given every assistance that his great knowl- 

 edge of the order could suggest, besides placing the rich collect- 

 ions of Harvard Univcrsitv at our disposal; and it is but justice to 

 say that the work would have been well nigh impossible hail it 

 not been for his masterly I^ibliographical Index. Dr. N. L. Brit- 

 ton has also enabled us to studv the valuable collections of Colum- 

 bia College, cspecialh' desirable on account of its Torrex collec- 

 tion. The Philadelphia Acadenn also generously submitted their 

 collection of Umbellifers to our inspection, a \ er\' importaiit aid 

 on account of the number of Xuttallian t\pes it contains. The 

 herbarium of the Agricultural Department was also placed at oui- 



D. H. HILL LIBRARY 1^8819 

 North Carolina State College 



