1254 J^iiiri rsHi/ of Califoniid P\<hJ'\r(it\(nis in liutain/ r^'<"--7 



n'iK'lics — 20^ h\ (iuayulc on the (itlii'i- hiind. is Too tciuU'r i'of any 

 but oui- uaniici' valleys and i'\cn there its cultivation is apparently at- 

 tended with soiiu' I'isk. Its intr(xluction into this country is an exten- 

 sion of its natural range, whei'eas the cultivation of (.'hrysothamnus 

 would be merely the utilization of a native plant adajtted by nature to 

 our region. 



(3) Chri/sotJiamniis is verj' resistant to alkali, often growing on 

 soils too alkaline for any ordinary agricultural ci-op. It could there- 

 tVti'e be grown on land not now utilized and which could V)e obtained 

 for a very moderate price. Guayule is sensitive to alkali. 



(4) The water ri^piirement of Chrijsotliannius is considerably less 

 than that of Guayule. It could certainly be grown without irrigation 

 on the cheap lands mentioned in paragraph 3. 



(5) The })i-oduct is superior to that of Guayule (see ]). 188). It 

 would bring a higher price in the market and if need arose would 

 more nearly replace the tine imported rubbers in oui' industries. 



(6) Chrysothanniiis is more easily and cheaply propagated, both 

 from seed, which form in abundance and are easily germinated, and 

 vegetatively. Both old plants and seedlings may be transplanted with- 

 out loss. 



(7) Certain cultural practices have been developed in connection 

 with Guayule that result in an increased yield of i-ubber, and methods 

 of operation have been devised that permit of cheap handling through 

 the use of machinery, so that the crop is said to be "machine-grown." 

 There is no reason to suppose that similar practices and methods cannot 

 be perfected for ('Jirijsothannius. The larger size of the shrubs and 

 tlieir habit of throwing up numerous new shoots when cut back indi- 

 cate^ the possibility of increasing the tonnage of rubber carrying shrub 

 by the cutting back of the tops (see pi. 20). Experimental work along 

 these lines has not yet progressed to a stage where estimates would be 

 warranted, but it is believed that a method can be worked out that 

 will multiply by a considerable factor the tonnage of shrub per aere- 

 3'ear. It is possible that such mani]nilation may at the same time 

 favor an increased formation of rubber in the tissues. 



It would seem, therefore, that the possibilities of ('hrj/soflidnniKs as 

 a cultivated rubber plant should be looked into more closely. Any 

 spe<'ies which gives even the least promise should be thoroughly studied 

 in ortler to find, if possible, a new crop that will turn our waste lands 

 into productive fields and at the sanu^ time safeguard the nation against 

 a possible deficiency in rubber during critical periods. These investi- 



