450 MANUAL OF TROPICAL AND SUBTROPICAL FRUITS 



an important article of diet in many regions. It is eaten fresh, 

 dried, or prepared in various ways. Griffiths and Hare have dis- 

 cussed this subject fully in " The Tuna as Food for Man. " 1 The 

 ripe fruit contains : Total solids 19.66 per cent, ash 0.40, acids 

 0.18, protein 0.98, total sugars 13.42, fat 0.23, and fiber 2.79. 



J. W. Tourney, writing in Bailey's " Standard Cyclopedia of 

 Horticulture," says : "It has been ascertained that some of the 

 best varieties are capable of producing on lean, sandy or rocky 

 soil, ill-suited for growing ordinary crops, as much as 18,000 

 pounds of fruit to the acre. When it is considered that this 

 is equal to 2500 pounds of sugar, as well as other valuable 

 food constituents, it may be readily seen that the food value 

 from the standpoint of nutrition is considerable/' 



Little cultural attention is usually given to the opuntias in 

 the regions where they are grown for their fruit. To quote 

 Tourney again : " Plantations are usually made on dry ' slopes 

 of hills, as the plants do not thrive where there is much mois- 

 ture or on heavy clay soils. Joints, cut or broken from the 

 plants, are used instead of seeds, and are planted at distances 

 of 6 to 8 feet in furrows from 6 to 15 feet apart. No tillage is 

 practiced, as they grow rapidly, and in a few years smother out 

 all other growth. Before planting, the cuttings are exposed 

 in half sunlight from seven to fifteen days, that they may 

 partially wither, in order to facilitate rooting. 



" An important advantage in the culture of these plants is the 

 regularity of the yearly crop. They begin to bear in about three 

 years after planting, and continue in bearing for many years." 



Numerous varieties or forms, usually local in their distribu- 

 tion, are distinguished in Mexico and elsewhere. In spite of the 

 attention given in recent years to the improvement of this 

 fruit by breeding, still further advances must be made before 

 varieties are obtained which will become popular as table- 

 fruits among North Americans. 



1 Bui. 116, Bur. Plant Industry. 



