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POPULAR SCIENCE MONTHLY. 



The Climax plum is a cross of the bitter, flat, tomato-shaped Chinese 

 plum, Primus simoni, and the Japanese plum, Prunus triflora. The 

 Chinese plum produces almost no pollen ; hardly a grain of it is known, 

 not more than one could put in his eye without feeling it; but the 

 whole fruit shipping industry of the world has been changed by this 

 hybrid plum (Climax) produced by it. With many crosses of many 

 things it is certain that forms of great importance will come out every 

 year, though never in profusion. 



In developing a spineless 

 cactus for stock-feeding, selec- 

 tions were made from the three 

 hardy northern species, Opuntia 

 rafinesquii, 0, mesacantha and 0. 

 vulgaris; these were crossed with 

 0. tuna, 0. ficusindica and with 

 Original and Improved Beach Plum. a Small opuntia from Central 



America, almost thornless. 

 The cactus has smooth cotyledons, but the first bud is covered with 

 thorns. These thorns have also been eliminated by selecting the 

 smoothest individual seedlings without crossing. Crossing in this case 

 generally interrupts the process, as it brings out well-fixed ancestral 

 traits, but later, to combine the best qualities of several species, crossing 

 and selection must be resorted to. Examples seen were shoots of the 

 original stock, prickly; the second generation, slightly prickly; the 

 third, without thorns ; and later the spicules even within the substance 

 of the cactus have been removed so as to make the cactus very ex- 

 cellent food for cattle. This will have very great value in the arid 

 regions. Some cacti lose the thorns on the plant but retain them on 

 the fruit; others vice versa. By crossing and extensive and intensive 

 selection a cactus may be improved in various ways besides being de- 

 prived of thorns and of the internal spicules in six or less generations ; 

 these, by means of cuttings, may be multiplied rapidly to any extent, 

 but the process, to be complete, generally takes longer. This thorn- 

 less cactus should prove of very great value in the development of 

 desert regions as Arizona or Sonora, as the quantity of food produced 

 per acre is enormous. 



The Bartlett plum has the flavor of a Bartlett pear, but even more 

 strongly developed. The ' rice seed ' plum has extremely small seeds. 

 The stoneless plum is a cross of the French prune with a wild plum 

 having the stone almost eliminated by a fortuitous variation. The 

 result thus far is a great number of stoneless plums of good size, but 

 in flavor inferior to the best cultivated ones. These are being crossed 

 again to improve the flavor, and new selections made. 



Crossing the Japan and the New England chestnut (Castanea 



