Reprinted, without change of paging, from Journal of The Xew York 

 Botanical Garden 27: 154-158. 1926. 



WHY ARE CHESTNUTS SELF-FRUITLESS? 



It has frequently been observed that chestnut trees which stand 

 alone do not yield satisfactory^ crops of nuts. 



Dr. Wm. A. Taylor, Chief of the Bureau of Plant Industr}% 

 writing in the Standard Cyclopedia of Horticulture (Vol. 2, p. 

 745) summarizes this condition for the American group of chest- 

 nuts as follows : 



"Solitary trees are frequently sterile, although producing 

 both staminate and pistillate flowers, apparently requiring 

 cross-pollination to insure fruitfulness. This is especially 

 true of planted trees of this species on the Pacific slope, 

 w^here productive trees are reported to be rare." 

 It is quite probable that this statement applies equally well to 

 the varieties of chestnuts of the European and Japanese groups to 

 which many of the cultivated varieties belong. 



During the autumn of 1922 the writer had an opportunity to 

 observe the condition of sterility in two chestnut trees of unde- 

 termined variety growing apart from each other and isolated from 

 other chestnuts at Claremont, California. These trees were 

 heavily loaded with burs but those of one tree contained only 

 shriveled nuts without "meats" or embryos and in the several 

 bushels of burs from the other tree there were only about thirty 

 nuts which contained meats. The empt> nuts were much 

 shrunken with the sides pressed together. The trees bloom pro- 

 fusely and they bear many fruits but the burs rarely contain a 

 good seed. 



It was not possible for tlie writer to make proper tests to de- 

 termine if the seedless fruits on these trees develop entirely with- 

 out any pollination and if they will yield good nuts to cross-polli- 

 nation but perhaps the Y:\\\vv ma\- be assumed. 



