HORTICULTURE 153 



can live in a large orchard, especially if it is well tilled. As the extent 

 and thoroughness of cultivation increases, the number of these 

 natural insect aids to cross-pollination decreases ; hence it may become 

 necessary to keep domestic honey bees for this purpose. (Cornell 

 Ex. Sta. B. 181.) 



Hybrids. Where a cross is made between very different forms, 

 as between the sand cherry and the plum, the result is termed a 

 hybrid. The difference between crosses and hybrids is only one of 

 degree, and of late years there has been a tendency to do away with 

 the use of the term "hybrid" altogether. There is a common impres- 

 sion that hybrids are exceedingly rare and that they are of more 

 value than ordinary crosses, but such is far from being the case, as 

 they are frequently of but little value. 



While wild plants come nearly "true" from seed, cultivated 

 fruits, which have been developed from them, do not come "true," 

 but show a decided tendency toward the wild, inferior forms. Al- 

 though an occasional seedling may be a decided improvement over 

 the cultivated kinds, there is not one chance in a thousand of getting 

 better fruits than those we now have by growing the seeds of these 

 better sorts. This is due to the fact that we do not grow our fruits 

 from seed but by grafting, budding, etc. If they were grown from 

 seed for many generations it would undoubtedly be possible to get 

 them to come as true to type as do our garden vegetables. Since no 

 two plants are exactly alike, it is evident that the strongest tendency 

 in plants must be toward dissimilarity. Some cultivated fruit plants 

 that come most nearly true from seed are a few local varieties of the 

 peach, the Wyant plum, and such strawberries as the Alpine and St. 

 Anthony de Padua. 



The yearly round of activity of a plant is rapid growth in the 

 spring, during which time it is using up the store of plant food accu- 

 mulated the year before. After this rapid growth has passed there 

 follows a slower period of growth, in which the wood is said to ripen ; 

 that is, it becomes hard by reason of its cells becoming filled with 

 starch or other plant food which is stored for use in starting growth 

 in the spring. When this storing process is completed growth stops. 

 When there is warm, moist weather, late in autumn, growth some- 

 times starts again and a portion of this plant food is thereby changed 

 into unstable compounds which, when exposed to freezing, results in 

 winterkilling. Some varieties are much more liable to start in this 

 way than others. (U. S. E. S. B. 178.) 



Rapid Wood Growth. It has been often observed that trees 

 making very rapid wood growth fail to bear heavy crops of fruit. 

 This is well illustrated in the case of young trees which fail to bear 

 during the first years of their growth. The reason for this is not 

 well understood, but it is fully established that the growth and re- 

 productive forces are in a measure alternative and that whatever 

 favors the one will retard the other. While over-rapid growth always 

 tends to lessen the fruitfulness of a tree, lack of food or insufficient 

 nourishment will produce the same effect. The remedy in either 



