6 BULLETIN 728, U. S. DEPARTMENT OF AGRICULTURE. 



such prices as stockmen can well afford to pay for the work to be 

 done; (4) that the power required for the work is such as is supplied 

 by the kind and size of engine frequently found on the average stock 

 ranch or which may be purchased at a reasonable price; and (5) that 

 the use of these machines renders available a supply of low-grade 

 feed which will save the lives of animals that would otherwise starve. 

 (See PI. II, fig. 1.) 



KINDS OF FEED. 



As has already been stated, the feeding of sotol is not new nor is the 

 idea of using certain other plants that have either stems or leaves (or 

 both) that are more or less thickened. All the development of the 

 use of prickly-pear has come about from carrying out this idea with 

 respect to certain cacti. It is one of the purposes of this bulletin to 

 summarize as definitely as possible the available data as to possible 

 sources of stock feed of this kind. 



One difficulty to be overcome, which is a cause of considerable 

 misunderstanding and frequent differences of opinion, arises from the 

 confusion of the various common names in use for the different plants 

 and the similarities in their appearance. 



The plants which may be chopped up and used as emergency feed 

 belong to two families, embracing 4 or 5 different genera and as 

 many as 12 to 20 different species. Almost any one of them may be 

 very easily confused with one or more of the others that are similar 

 in appearance. Differences which are very easily seen to exist among 

 the flowers and fruits, the basis of most botanical classifications (PI. V, 

 fig. 1), are not to be seen except in the flowering season, and most 

 people have not examined them at that time. The differences in the 

 leaves and habits of the plants b} T which they can be distinguished 

 when the plants are not in bloom or in fruit are here described. 



SOAP WEED. 



In the region between Pecos, Tex., and Tucson, Ariz., and south of 

 Safford or Clifton, Ariz., and Silver City and Socorro in New Mexico, 

 on the sandy plains, occurs in greater or less abundance a narrow- 

 leaved yucca that is usually referred to by the English-speaking popu- 

 lation of the region as soap weed. It is one of the commoner, and 

 frequently the commonest and most conspicuous, of the desert shrubs. 

 It is often called amole or by its proper Mexican name of palmilla (the 

 little palm), and in the region about Thatcher, Ariz., it is called ooce, 

 which is probably an Indian name for it. This is one of the two com- 

 monest yuccas of a region where there are several, and is known 

 botanically as Yucca elata (the tall yucca). (PI. Ill, figs. 1 and 2; 

 PI. IV, fig. 1.) It is called soap weed and amole because its roots 

 (and stems) are frequently used as a soap substitute. This name 

 soap weed is not distinctive of any species, though most commonly 

 applied to the one mentioned, but is often applied to other plants that 



