MICHIGAN ACADEMY OF SCIENCE. l29 



CRAT^GUS IN SOUTHERN MICHIGAN. 

 C. S. Sargent. 



Professor Charles S. Sargent, of the Arnold Arboretum, Jamaica Phiin, 

 Mass., at the request of Dr. W. J. Beal, prepared for publication a i)aper 

 which embodies the results of his studies of the Thornapples or Hawthorns 

 of Michigan, and the adjacent region. The paper was presented to the 

 Michigan Academy of Science to be published in the present volume of Re- 

 ports, but in the hope that it might be printed in time for use during the 

 ,field season of 1907, it was decided to request the State Board of Geological 

 Survey, through the State Geologist, Alfred C. Lane, to include the paper 

 in the Report of the Board of Geological Survey for 1906, as a contribution 

 to the Biological Survey of the State, now being conducted. This request 

 was very kindly granted, and information regarding the complete paper 

 may be had by application to the State Geologist, Lansing, Michigan. 



In order that the members of the Academy may have the benefit of the 

 directions for collecting these interesting plants, however, the introduction 

 to Professor Sargent's paper, and his instnictions for the collection of usable 

 material are here given. Those who are willing to systematically collect 

 good and complete specimens of Crataegus in any part of the state can ma- 

 terially help in the work of extending our knoAvledge of the number and 

 distribution of the species of this most interesting genus of trees. 



c. A. D. 



Professor Sargent says: 



In the following paper I have attempted to give an account of the species 

 of Crataegus that are now known to occur in the southern part of the state 

 in the hope that its publication, by calling attention to the richness of the 

 Michigan flora in the plants of this genus, may encourage its more general 

 study. 



Southern Michigan forms the western extension of what is perhaps the 

 richest Crataegus region in the world; certainly in no other part of the world 

 where the genus has been at all carefully studied are there so many species as 

 in the territory extending from the valley of the Genessee river in New 

 York, up both sides of the Niagara river and through Southern Ontario 

 into Southern Michigan, and nowhere are there more distinct species. 



Of the genus as it occurs in Michigan little is yet known. It has been 

 carefully and systematically studied only on Belle Isle, in the Detroit river, 

 by Mr. 0. A. Farwell, in St. Clair county, by Mr. C. K. Dodge, and in the 

 neighborhood of Grand Rapids by Miss E. J. Cole. It is now possible, how- 

 ever, to distinguish fifty-five species, and of these twenty are now first de- 

 scribed. Nineteen others briefly described by Ashe from St. Clair county 

 are also described in this paper from material furnished by Mr. Dodge. All 

 the Michigan species described by Ashe have been identified with the ex- 

 ception of C. passena, collected at Port Huron, and probably one of the 

 Flabellatus, C. fallax, from "rocky hills" near Port Huron, and C. borealis, 

 without other locality than "Michigan." The latter species is given in 



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