72 
vision of Forest Pathology, Bureau of Plant Industry, of the 
United States Department of Agriculture, from American chest- 
nuts planted at the Government nursery at Bell, Maryland. For 
the pistillate trees, ie. the female, or nut-bearing parents, we lim- 
ited our work to the use of two of the more promising Japanese 
trees—those of Mr. Paul Hammond and of Mr. John W. Minturn, 
both at Syosset, Long Island—and to young shoots of American 
chestnut which we happened to find on the estate of Mrs. James 
A. Burden. The Minturn tree is a very fine specimen, one of the 
best in the region, but in past vears we have had no success in 
securing hybrid nuts from it. This year, therefore, we concen- 
trated our efforts on it. As a result, out of a total of thirty-nine 
hybrid nuts collected in the fall, fifteen were from the Minturn 
pas 
tree. igure & shows, slightly reduced, one of the burs resulting 
from the cross-pollination of the Hammond tree. This bur, which 
yielded three nuts, is of unusually large size, about four inches in 
its median horizontal diameter. The details of the hybridization 
work in 1933 are summarized in Table II, below. These nuts 
Taste Il. ANArysis or Cross-PoLLINATIONs, 1933 
Minturn Hammond Burden Total 
No. of branches bagged . 60-+- 7 selfed 61 + 30 selted 13 171 
No. of flowers pollinated 95 76 32 203 
No. of flowers developing 
SRD | ec eae cae recreate 14 15 | 30 
No. of nuts ripened ..... 15 23 1 39 
* Because of severe storms, we suffered unusual losses of obviously ma- 
tured nuts. 
were all planted in sand immediately after collection, and the 
pots placed out of doors in cold frames for overwintering. 
A notable feature of our hybridization work this year was the 
use, for the first time, of an American tree as the pistillate parent. 
Iextensive crossings of this type would be very desirable, but here- 
tofore we have been limited to Japanese trees for the female par- 
ents of our hybrids, because of the scarcity of flowering American 
chestnuts in the environs of New York. Good sized shoots (to a 
