62 MASSACHUSETTS HORTICULTURAL SOCIETY 



is that whereas Downing's plums were pure-bred species, 155 of the 

 present cultivated plum flora are hybrids between species. Downing 

 could recommend plums for only a few favored regions. Some kind 

 of plum can be grown now in every agricultural region in North 

 America. Even more remarkable is the part hybrids have played 

 in the evolution of American grapes. At the beginning of the 

 nineteenth century, the grape could not be called a cultivated crop 

 on this continent. Now there are 16 species and 1,194 varieties, 

 the most significant fact being that 790 or three-fourths of the 

 total number are hybrids. The grape through hybridization has 

 become one of the commonest cultivated plants. The genus 

 Ihibus promises to attract and distract horticulturists next. As 

 nearly as I can make out there are about 60 species of Ruhus in 

 North America. In the two completed parts of Focke's " Species 

 Ruborum," 273 species are described. Raspberries, blackberries, 

 dewberries and their like hybridize freely and we already have in 

 the loganberry, the purple-cane raspberry, the wineberry and in 

 the blackberry-dewberry crosses valuable fruits. If any consider- 

 able number of Focke's several hundred species can be similarly 

 mixed and amalgamated, the genus Rnhus will be one of the most 

 valuable groups of fruits. 



The speaker a few years ago made a study of cultivated cherries. 

 When the work began a few years ago about a score of species were 

 in sight. Koehne, a recent botanical monographer of the sub- 

 genus Cerasus, to which our edible cherries belong, describes 119 

 species, many of them but recently collected by Wilson in Asia. 

 There are enough hybrids betw^een species to indicate that culti- 

 vated cherries will some time be diversified as plums and with 

 quite as much advantage to the fruit. 



Webber's and Swingle's work in breeding hardy citrus fruits; 

 blight-resisting pears as a result of crossing Pyrvs covimunis and 

 Fyrvs sinensis; Burbank's spectacular hybrid creations; the 

 diversity of types of tomatoes, potatoes, egg-plant, peppers, beans, 

 cucurbits and other vegetables, not to mention roses, chrysanthe- 

 mums, orchids and innumerable flowers, suggest the possibilities 

 of hybridization. We have not done what lies within our reach 

 in crossing cereals — corn, wheat, oats, rye, buckwheat, the last 

 especially, remain yet to be touched by the magic wand of hybridi- 



