24 T O R R E Y A 



Cryptostegia for rubber production has been planted over a large acreage 

 in Haiti. The project originally intended to contain 100,000 acres, is variously 

 estimated as 40,000 to 43,000 acres at expiration of the planting deadline on 

 March 31, 1944. 



Goldenrod. The suggestion for the use of goldenrod as a source of rub- 

 ber goes back to the work of the late Thomas A. Edison (Polhamus 1933). 

 Edison directed a survey of some 17,000 samples of plant material from several 

 different species native to this country. From this survey he decided that 

 certain species of goldenrod represented the most promising plants for a 

 possible development of domestic source of rubber which could be used during 

 an emergency which cut off other rubber sources. At Mr. Edison's death his 

 selected goldenrod material was turned over to the United States Department 

 of Agriculture. Four species, Solidago altissma, S. gigantea, S. leavenworthii, 

 and S. sempervirens were selected as the most promising. 



In cultivation Solidago leavenworthii, native to Florida and extending 

 Xorth only to Georgia and South Carolina, has proved most satisfactory as 

 to rubber yields. Selected strains of this species have given indicated yields 

 of from 50 to 75 pounds of rubber per acre in the first year. These selected 

 strains are propagated by stolon cuttings, a method which permits a very 

 large annual expansion. 



Limited to certain areas in the South, goldenrod has an advantage in that 

 its soil requirements are not exacting. Average quality sandy loam "cotton 

 land" is quite satisfactory. 



At one time in the developmental program the goldenrod scab, caused by 

 Elsinoe solidaginsis, presented a serious problem, but the better selected 

 strains are almost completely immune. Goldenrod is harvested in the fall of 

 the year by mowing and the leaves or the leaves and the stems are utilized 

 for extraction of rubber. Extraction has been generally successful only by 

 solvent processes. There is a possibility that the. ligno-cellulose leaf residues, 

 some carbohydrates and some proteins may provide by-products. 



Taraxacum kok-saghyz, better known simply by its descriptive species 

 name, which means "chew-root" in the Kazak language of its native habitat, 

 is a comparatively new addition to the roster of potentially important rubber- 

 bearing plants (Brandes 1942b). It was discovered in 1931 by a Russian 

 expedition sent out to collect native Russian plants with a view to cultivating 

 them as a nucleus of a domestic rubber supply. The plant was found at an 

 altitude of 5,500 to 6,500 feet in soil designated as somewhat saline. Stands 

 of about 5,000 acres were reported. The temperature of the region ranges, 

 according to reports, from -2° F. to — |— 59° F. 



When grown under favorable conditions, kok-saghyz looks much like our 



