230 PLANT-BREEDING 



planted in the spring and had already produced a first set 

 of numerous disc-like branches. They were expected to 

 make two or three more sets in the same year and to fill in 

 the large spaces which were left between them at the time 

 of their planting. They varied in the size, form, and color 

 of the pods, and probably, also, in their nutritious quaUties, 

 and were grown as a direct test of these points. The value 

 of these hundreds of plants which will, on the average, 

 produce fifty pods each in a year, may be deduced from the 

 fact that he had sold five of the pods to an AustraUan firm 

 and was building a new and larger residence from the sum 

 they had brought him. 



It would, of course, add highly to the value of this race 

 if it could be made constant from seed. It is evident that 

 a rapid spreading, as well as the treatment on the farms, 

 would be made more easy by such a change. I saw numer- 

 ous wooden seed boxes with small seedUngs, but almost all 

 of them were spiny. Thousands were rejected, and only those 

 which showed a distinct diminution of their spines were 

 selected and planted out. Large beds with young spineless 

 plants were seen in his garden. Burbank estimates, from 

 the present extension of uncultivated lands fit for the pro- 

 duction of cacti, that his spineless and edible varieties may, 

 in time, double the population of the earth. At least they 

 promise to do more for the world, in a material way, than 

 any other of his productions, but much work will still be 

 required before even an essential part of his hopes can be 

 brought into execution. 



Beautiful and striking sports are sometimes offered by 

 hybrids which revert to a quality of one or more of their 

 pure ancestors, this mark not yet being displayed in the 

 previous hybrid generations. An instance of this we admired 

 among his Callas. Hitherto his hybrids had varied in the 

 color of their spathes from white to a more or less intense 



