1919] Hall-Goodspecd: CJinjsil 201 



pears to be a dwarf form of viridulus. Most of these small plants 

 carry less than two or three per cent of rubber and are of but little 

 practical importance. 



C. teretifoUus, carrying about 2.7 per cent of rubber, grows sparse- 

 ly on the Rosamond Hills but may be abundant on the mountains 

 to the west of Antelope Valley. Around the borders of the Mojave 

 Desert, especially toward the west, are scattered stands of two other 

 low-grade rubber shrubs, Haplopappus monactis and H. lineanfolius, 

 but these are of little value. 



The amount of rubber in the shrub which we have located in Dis- 

 trict 2, taking no account of the species mentioned in the preceding 

 paragraph, is estimated at 400,000 pounds. 



c. DISTEICT 3— NOETHEASTERN CALIFORNIA AND ADJACENT 



NEVADA AND OREGON 



The principal areas thus far located in this district are on the alka- 

 line plains of eastern Lassen and Modoc counties, California, where 

 Rabbit-brush, in the consimilis form, makes pure stands over many 

 thousands of acres. The percentage of rubber in these plants is ap- 

 parently quite uniform and runs a little more than two per cent. There 

 are about two square miles east of Honey Lake where the plants aver- 

 age sixteen feet apart and two representative samples weighed ten and 

 twenty-eight pounds, respectively. In the vicinity of Karlo we find 

 about seven square miles covered by a nearly pure stand of the shrub ; 

 an area of about the same size occurs on Painter 's Flat ; and still an- 

 other to the west of Madeline. The plants on these tracts are often 

 smaller than in the Honey Lake Valley (two taken near Karlo weighed 

 under two pounds each for the woody portion), but when small they 

 grow closer together. There is an area of 1000 acres south from 

 Ravendale, covered with medium sized shrub. About twenty square 

 miles have been located by Mr. L. S. Smith in northeastern Modoc 

 Countj^, where the Rabbit-brush comprises about 25 per cent of the 

 vegetation, but it occurs chiefly in one of the gray-foliaged varieties 

 and is therefore poor in rubber. There are some unexamined areas of 

 consimilis west of Alturas, several sections of the gray form in Butte 

 Valley and around Klamath Lake, and some extensive areas of con- 

 similis on the Klamath River drainage of north-central Siskiyou 

 County, California. 



In southeastern Oregon, the Rabbit-brush was found by Mr. J. R. 

 Bruff to exist only in small stands. The largest area located is in 



