CEETATN DESERT PLANTS AS EMERGENCY STOCK FEED. 9 



machine, like a silage cutter, if the knives are kept sharp. The 

 chemical analysis indicates that this material is of about the same 

 feeding value as the other plants here discussed. 



SOTOL. 



Sotol * is the name applied to all species of Dasylirion in the 

 Mexican border region, as well as in northern Mexico. In south- 

 central Arizona it is sometimes called sotoli. These plants grow- 

 only on the rocky foothills of the mountains and part way up the 

 mountain sides. They are easily recognized by their numerous long, 

 flexible, strap-shaped leaves, bearing yellow curved spines on their 

 margins. Over small areas they are sometimes very abundant, but 

 such thick patches are not common. 



KEYS TO PLANTS DESCRIBED. 



For convenience in identifying the above-mentioned plants when 

 not in bloom the following artificial keys may be used. 2 



Key to the genera. 



I. Leaves tipped with a more or less rigid spine. 



A. Margins of the leaves bearing a threadlike fiber or sometimes 



without the fiber but having a minutely toothed, horny 



margin 1. Yucca. 



This genus contains the soap weed, one of the plants 

 called bear-grass, the Spanish bayonet, etc. 



B. Margins of the leaves bearing conspicuous recurved gray, 



brown, or black spines 2. Agave. 



This genus includes the century plants, lechuguilla, 

 mescal, and maguey. 



II. Leaves usually frayed at tip, never having a terminal spine. 



C. Leaves thin and strap shaped, margins bearing small yellow 



curved spines 3. Dasylirion 



The species of this genus are all called sotol. 



D. Leaves narrow, usually nearly as thick as they are wide, mar- 



gins smooth or very minutely and sparsely toothed, sometimes 



tapering into a long, slender, curved or bent tip. 4. Nolina. 



This includes the sacahuista and another plant called 

 bear-grass. 



1 The spelling is Spanish though the word may be Indian, and the accent is on the second syllable. The 

 Americans are beginning to drop the "1," put the accent on the first syllable, and apply the word to the 

 soap weed in the Deming to Bowie district where they are not very well acquainted with the real sotol. 



2 To determine the name of a plant by the use of the key, look first at the tips of the leaves. If the leaf 

 ends in a sharp hard spine, the plant will be found in group I; if not, then look in group II. If the plant 

 belongs to group I, then look at the leaf margins and see whether they bear hooked spines. If they do, 

 the plant is an Agave and is one of the group of plants to which the century plant belongs. It is necessary 

 to take the steps in determination in the order indicated or incorrect conclusions will be reached. Thus, 

 Dasylirion has hooked spines along the margins of the leaves, but the leaves are not spiny pointed. Al- 

 ways settle the question under the major subdivision first before passing to questions of the next order 

 of rank. At the end of the series of questions will be found the botanical and common names of the plant 

 under examination or some very near relative of it. The attempt here is not so much to be technically 

 accurate as a botanist as it is to answer the natural questions of stockmen with a degree of accuracy sufficient 

 for their purposes. 



69803°— 18— Bull. 728 2 



