256 Brown: THE GENUS CRATAEGUS 
parts of the country, especially in the eastern half of the United 
States. He, as was stated above, believes in reducing the number of 
species ; he does this by making certain species of different authors 
equivalent, and by reducing other species to the rank of varieties. 
His discussion in regard to the questions is as follows: 
Systematic botanists did not know the species in America 
largely because they never saw them. The Gray Herbarium and 
the Torrey Herbarium were both very scanty in Crataegus. The 
manuals took most of the forms they had. The coastal plain has 
very few Cratacgi, and that is where a large share of the early 
collecting was done. The European botanical gardens had many 
more American species than were known here, and it is through 
them that the work commenced. 
Crataegus plants produce much good seed and the plantations 
at Biltmore, Arnold Arboretum, and at the New York Botanical 
Garden, show that the forms of the genus reproduce themselves 
surprisingly from the seed (leaf characters only ; trees mostly not 
yet fruiting). They doubtless will hybridize, and there are prob- 
ably mutations, too. 
Dr. Ezra Brainerd, ex-president of Middlebury College, 
Middlebury, Vt., was another authority questioned. He writes: 
The queries that you raise in your letter of Nov. 15 regarding 
Crataegus are queries that have been puzzling me for over six years, 
and I am not even yet prepared to answer them with any positive- 
ness. The problem is part of a larger one that I have been dili- 
gently studying as it is presented in the genus V7o/a; and here 
with very satisfactory results. Experimental work in Crataegus is 
difficult, as in this genus it is about 7 to 10 years from generation 
to generation : Vo/a affords a new generation each year. So I shall 
be able to give only brief and inadequate answers to your questions. 
1. I fancy the systematic botanists did not “ discover the large 
number of species of Crataegus years ago,” because (a) they had 
broader conceptions of what constitutes a species than most modern 
botanists have ; many recently made species used to be considered 
mere forms or varieties; (4) the genus Crataegus, I believe, has 
vastly increased in individuals and in “ forms” in the northeastern 
U. S. since the forests were cut off; specimens are rarely found in 
the original forests of this region. But the plants rapidly take 
