HORTICULTURE 305 



averages about .45. It is porous because of the great number and 

 large size of the vessels in the wood. These, as well as the wood 

 cells themselves, do not become solid when the sap wood changes into 

 heart wood, but retain more or less their open character. It thus 

 absorbs or loses water, swells or shrinks readily, according to the con- 

 dition of the air. Although light and brittle, and hence unsuited 

 for some uses, its superior durability makes it one of the best of our 

 native woods for many purposes. The bark has value for tanning, 

 although not held in as high esteem for this purpose as that of 

 several other trees. 



The fruiting of the chestnut does not ordinarily occur until the 

 tree has become at least ten or twelve years old, and when they are 

 crowded not until much later, and then sparingly only on its upper- 

 most branches. Low, round-headed trees having ample room for 

 development, are the only ones which bear early and liberally. 

 Hence, isolated trees on the borders of woods and fields are always 

 the most productive. Blossoming occurs from June to July, accord- 

 ing to latitude, and the fruits mature in from two and one-half to 

 three months. The flowers are separated; the staminate, or male, 

 conspicuous from the long finger-like spikes of the cluster on which 

 the whitish flowers are arranged; the inconspicuous pistillate or fe- 

 male flowers are in small compact clusters, each of which latter is sur- 

 rounded by prickley bracts which grow rapidly after the flowers are 

 fertilized, forming the globular bur. Apparently fertilization is 

 accomplished by the action of the wind, and there are some facts 

 which seem to indicate that cross-fertilization is necessary. Lack 

 of fruitfulness is due to a variety of circumstances, and here, as 

 with other plants, the cause- must be sought for sometimes outside 

 of the flower. The nuts are too well known to need description. 

 They are comparatively uniform in size, but vary greatly in abund- 

 ance and perfection in different years. Imperfect fertilization and 

 insect injury are the chief causes of this. 



The native chestnut is but little variable in any respect, and has 

 given scarcely any varieties, the history of which is known, or which 

 are plainly distinguished from the type. 



The European chestnut, however, has not only a marked natural 

 peculiarity in the greater size of its nuts, but has given rise to 

 varieties which are much superior to the wild type, and are highly 

 valued by cultivators. Over thirty have been named and the com- 

 mon species is said to be but little used except as stock upon which 

 to work the others. The varieties in most frequent cultivation are 

 esteemed for the superior quality of their fruit more than for any 

 other reason. The trees do not grow so large as the American, and 

 come into bearing more quickly. 



Within the past few years species from Japan have been intro- 

 duced into the United States. Unfortunately they do not appear 

 to be entirely hardy on their own roots, except in the south and some 

 favored districts in the middle states. They are quite dwarf in 

 habit, produce nuts larger even than the European, and begin to 

 fruit when they are but four or five years old. 



