1919] Ilall-Goodspeed : Ruhher in West American Shrub!- 



269 



ically, separated in water, and found to be rather soft and dark colored. 

 It was not subjected to detailed examination. The recovery of any 

 considerable amount of rubber from the wild shrub is practically im- 

 possible because of the verj' limited known supply. It is conceivable 

 that under cultivation it might grow to good size and at the same time 

 retain its fairly high rubber content and that both the size of plant and 

 percentage of rubber could then be increased by selection or breeding, 

 but the outlook for this is not promising. 



Six samples have been examined and five of them are reported on 

 below. A considerable variation in the rubber content is to be expected 



since much depends upon the amount 

 of dead wood present in the sample. 

 Usually this is considerable since the 

 plants are very old and grow under 

 (^xtremely adverse conditions. The 

 analyses are for the whole plant 

 (after the obviously dead branches 

 had been removed) except that only 

 tli(^ upper portion of the root is in- 

 cluded. One other sample (438, 

 from near Deep Spring Valley, Cali- 

 fornia) was analyzed with the result 

 that the amount of the benzene ex- 

 tract was negligible. This is omitted 

 from the table since the plant was 

 not in a condition to permit of a 

 positive identification. It may be- 

 long to some other species or even 

 to another genus. 



Fig. 2. Haplopappus nanus, 



plaut no. 200. Beutoii Hills 



California 



illustrated. IV2 feet. 



Total height as 



Table 3 — Chemical Analyses 



*Based on air-dried sample analyzed by Professor P. L. Hibbard; if perfectly dry the benzene extract 

 would probably be between 9.fi and 10 per cent. 



