188 TJniversiiy of California Puhlications in Botani/ [Vol. 7 



Service; Mr. Geo. E. Moore, U. S. Forest Service; Mr. R. C. North, 

 IMcGill, Nevada ; Mr. S. B. Parish, San Bernardino ; Mr. George Park, 

 U. S. Forest Service ; ]\Ir. W. O. Sander, Center, Colorado ; Mr. Ta S. 

 Smith, U. S. Forest Service; Mr. O. P. Stilwell, Ogden, Utah; .Mr. 

 J. Sutcliff, Sntcliff, Nevada ; Professor J. J. Thornber, University of 

 Arizona; Mr. H. B. Way, Montello, Nevada; Professor A. 0. Weese, 

 Universitj^ of New Mexico; ]\Ir. Kirk Whited, Redmond, Oregon. 



For courtesies extended in connection with the field experiments, 

 chiefly through the granting of the use of land and assistance in fenc- 

 ing, we are indebted to Messrs. George R. Shuey, Independence, Cali- 

 fornia; W. H. Davis, Benton, California; and Eugene L. Dutertre, 

 Golconda, Nevada. 



To all of those who have assisted in the work, the authors tender 

 their sincere thanks. 



III. NATURE AND PROPERTIES OF CHRYSIL 



Chrysil is the name here proposed for the rubber prepared from 

 any form of Chrysothamnus nauseosus. It was suggested by Dr. 

 Frederic E. Clements and is selected because of its euphony and 

 brevity as well as for its suggestion of the botanical name of the plants 

 from which the rubber is obtained. "Chrysothamnus'' in turn, is 

 derived from two Greek roots signifying "golden" and "wood." 



The first samples of Chrysil were prepared for us by mastication 

 from shrub of the viridulus form by Paiute Indians at Benton, Cali- 

 fornia. These pieces were in the form of cylinders three-fourths to 

 one inch long by about three-eighths of an inch in diameter. They 

 included, in addition to the rubber, small amounts of resin, fiber, and 

 other impurities. They were brown in color, firm, scarcely if at all 

 tacky, and seemed to possess considerable strength and elasticity. Two 

 experts accustomed to the handling of crude rubbers declared them to 

 be "of good quality and considerably better than rubber prepared 

 from Guayule." These samples were exposed to air and liglit and 

 underwent a gradual change, so that at tlie end of a year they were 

 black in color and quite tacky on the surface, these changes doubtless 

 being due to impurities. 



Twenty-five pounds of viridulus shrub were gathered from the flats 

 at Benton and s]iii)ped to Dr. David Spence, Chairman of tlie 

 Subcommittee on Rubber and Allied Substances of the National Re- 

 search Council, with the request that he prepare rubber from it and 



