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THE POPULAR SCIENCE MONTHLY 



Fig. 7. Pkobably the best stand of Guayule in Mexico, Sierka Gojada, Dgo. 



The guayule shrub, having the low, tree-like habit of many desert 

 perennials, belongs to the family Composite of which our daisies and 

 dandelions are familiar examples. The most obvious proof of this re- 

 lationship is seen at once in the flowers, which, while not very daisy- 

 like at first glance, are seen in somewhat closer examination to follow 

 the same pattern. Instead, however, of the rather numerous white rays 

 surrounding the yellow center of the well-known daisy, in the guayule 

 the short rays are but five in number, and these, as well as the relatively 

 large disc, are of a uniform pale, dullish yellow. The flowers, unusually 

 for the Composite, have a distinct and very pleasing fragrance, and are 

 visited, and incidentally pollinated, by various small insects, even 

 mosquitoes. The leaves, which may or may not be lobed, according to 

 their development, are clothed with a dense, smooth covering of T- 

 shaped hairs, imparting to them the silvery sheen characteristic of the 

 shrub as a whole. 



The smaller twigs are similarly clothed, the hairiness giving way at 

 length to a smooth gray bark, which, with advancing age, becomes 

 longitudinally fissured. On the oldest and largest stems, transverse 

 Assuring takes place. On the whole, however, the surfaces of the 

 branches are smooth and gray, contributing to the general neutral as- 

 pect of the plant. But most striking of all the characters is the "feel" 

 of the lesser branches when bent, suggesting a weak wooden rod encased 

 in a firm rubber tube. The branches have little strength, the mechan- 

 ical elements of the wood being relatively few. An examination of a 



