Rbodora 
JOURNAL OF 
THE NEW ENGLAND BOTANICAL CLUB 
Vol. 10. 
May, 1908. No. 113. 
THE CRATAEGI OF THE NORTHEASTERN UNITED 
STATES AND ADJACENT CANADA. 
W. W. EGGLESTON. 
THE genus Crataegus presents an interesting problem, and one 
for the study of which we are just beginning to get sufficient data. 
Up to ten years ago the American species of this genus were much 
better known in European botanical gardens than at home; and one 
of the most vexing problems of the present in regard to the group is to 
know precisely what has been meant by the species described in 
Europe. 
In preparing a treatment of the genus soon to be issued I have 
endeavored, first to give a clear characterization of the different sec- 
tions, with good keys; second to take up the more important pub- 
lished species and varieties, without even pretending to deal with 
every form that may prove worthy of recognition. Much more 
thorough work needs to be done in the field, and careful cultural 
experiments will have to be made, before the genus can be exploited 
finally. 
The part of northeastern North America that really needs the 
most exploration in connection with this genus is southern Virginia, 
east of the Blue Ridge. Here should be found a number of the Flavae 
and other southern forms. Profitable work, however, can still be 
done all over the northeastern states and in adjacent Canada, both 
in extending the known ranges of old species and in finding new forms. 
In my judgment much of the trouble found in Crataegus arises from 
hybridization, and why may not mutation be another disturbing ele- 
ment? Along these lines there is a fine field for experimental work. 
Unhappily, such investigation in the case of Crataegus offers much 
greater difficulty than in Viola where the whole life history can be 
observed within a year or so. In Crataegus it would require perhaps 
