98 



EVOLUTION AND ANIMAL LIFE 



leaves, from two to three feet long, having a sweet odor like that 

 of apples. This hybrid produces no nuts, but curiously enough 

 the result of the reverse hybridization (i. e., pollen from nigra on 



FIG. 64. Hybrid seedling cactuses, Opuntia, after six months growth, showing num- 

 erous varieties. (From photograph by Burbank.) 



pistils of Californica) produces in abundance large nuts of a 

 quality superior to that possessed by either parent. 



Of new vegetables Burbank has introduced besides the Bur- 

 bank and several other new potatoes, new tomatoes, squashes, 

 asparagus, etc. Perhaps the most interesting of his experiments 

 in this field is his attempt, apparently destined to be successful, 

 to produce a spineless and spiculeless and unusually nutritious 

 cactus (the spicules are the minute spines, much more danger- 

 ous and harder to get rid of than the conspicuous long thornlike 

 spines) edible for stock, and indeed for man. This work is 

 chiefly one of pure selection, for the cross-bred forms seem to 

 tend strongly to revert to the ancestral spiny condition. 



Among the many new flower varieties originated by Bur- 

 bank may be mentioned the Peachblow, Burbank, Coquito, and 

 Santa Rosa roses, the Splendor, Fragrance (a fragrant form), 

 and Dwarf Snowflake callas, the enormous Shasta and Alaska 



