572 FORAGE PLANTS AND THEIR CULTURE 



The maximum yield of hay is probably about 2 tons to the 

 acre. 



Mexican clover may also be used for pasturage, and is 

 readily eaten by most farm animals. 



Seed is produced in abundance and can easily be saved, 

 but there is no commercial demand, as the plant when 

 once established volunteers year after year indefinitely. 

 Strictly speaking, it is not a cultivated plant at all, but a 

 useful weed comparable in this respect to crab-grass and. 

 bur clover. In the United States it is adapted only to 

 Florida and a relatively narrow region westward to Texas. 

 It succeeds best on sandy soils. 



688. Prickly pear (Opuntia spp.). These " pears " 

 are all natives to America. Some of the larger species 

 which grow to a height of from 3 to 6 feet or more and 

 which have flat, oblong or circular joints, have long been 

 utilized for forage. Some of these species, especially 

 those which are nearly spineless, were long ago introduced 

 into northern Africa, where they are grown quite extensively, 

 not only for the fruit but as feed for camels and bullocks. 

 In Texas they have been used as forage, especially during 

 periods of drought, for 50 years or more. In recent years 

 their cultivation for forage has received considerable atten- 

 tion in the United States. 



In the United States the larger species of Opuntia are 

 well adapted only to southern Texas and California and 

 portions of Arizona and New Mexico. They will with- 

 stand a temperature as low as 20 Fahrenheit for a short 

 time, but where the temperature often falls lower their 

 culture is not advisable. The spiny species especially 

 endure periods of drought remarkably well, but to obtain 

 a satisfactory growth under cultivation a good supply 

 of moisture is necessary. The root is comparatively 



