UEl'OUT OF THE STATE BOTANIST 1903 35 



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Xi:\>' YORK SPECIES OF CRATAEGUS 



The number of published species of Crataegus found in the 

 United States and Canada has increased surprisingly within the 

 last five jears. In the edition of Gray's Manual issued in 1890, 

 10 species and three varieties are recognized as belonging to the 

 territorj' covered by its flora. In the Illustrated Flora of Britton 

 and Brown, the second volume of which contains the descrip- 

 tion of the species of this genus and which was issued in 1897, 

 15 species and three varieties are recognized, but the territory 

 covered is somewhat larger than that of the Manual. Britton's 

 Manual issued in 1901 increases the number to 31 species and 

 retains but one variety. In the Silva of North America, volume 4, 

 published in 1892, 14 species are described, but in volume 13, 

 which appeared in 1902, the number of species is increased to 84 

 and the statement is made that this does not include some im- 

 perfecth' known arboreous species nor the merely shrubby species. 

 In the Flora of the Southern States by J. K. Small, issued in 1903, 

 185 species are diescribed. Varieties are not recognized. In an 

 article devoted to the species of Crataegus found in Rochester 

 and its vicinity and published in the Proceedings of the Rochester 

 Academy of Science, volume 4, 1903, C, S," Sargent has described 

 28 new sjiecies and recorded the occurrence of 13 others exclu- 

 sive of two introduced species which occasionally escape from 

 cultivation. This makes 41 species for the limited area of 

 Rochester and its vicinity, a number greater than that given 

 in Britton's Manual for the entire area covered by it two years 

 ago. From these data the inference is scarcely avoidable that 

 many of the recently described species must resemble each other 

 closely and must be founded on slight variations of specific char- 

 acters. If this inference is well founded, the conclusion is evi- 

 dent that such closely allied species can not be recognized without 

 a thorough knowledge of their distinguishing characters and this 

 knowledge can scarcely be obtained without careful study and 

 close observation. To properly represent such species in the 



