166 UnivcrsUu of California Publications in Botany fVoi,. 7 



ously araclinoid-pubcscciil. Sut'li arr .spi'ciiufns gatluTod by Leiberg 

 in eastern Washington uiulcr no. 884 and others by Marcus E. Jones 

 at Marysvah% Utah, uiidcf no. 5968. In northern Mono County, Cali- 

 t'ornia. is encountered a form in vvliicli the leaves are 2 to 3 mm. wide 

 and the inflorescence is more compact and rounded (H. M. H., no. 

 468), but in the pubescence of the corolla-tube and in all other 

 eiiaracters than those mentioned it is plainly nauseosus. Nearly 

 identical are specimens from Truckee, California (Ileller, no. 7192). 

 Another divergence is indicated by specimens with the broad leaves 

 and other characters of the Mono and Truckee collections just cited 

 but with a corolla-tube which is only crisp-pubescent as in most 

 varieties. A recognition of these forms would lead only to confusion 

 since further field studies would doubtless reveal still other divisions 

 that might be made. They are therefore retained in this paper as 

 only trivial variants of nauseosus. C. orthophyUus Greene, Pitt., 

 vol. 5, p. 62, 1902, known only from Plumas County, California, is 

 described as less than a foot high and with the tips of the corolla- 

 lobes as well as the tube long-villous. 



2. Chrysothamnus nauseosus var. hololeucus (Gray) comb. nov. 



liigclovia (/raveolens var. Jiolulcuca Gray, Proc. Am. Acad., vol. 8, p. 64-1, 

 1873. 



Shrub 6 to 18 dm. high and fully as broad, closely branched and 

 usuall}' of rounded outline, leafy throughout : herbage exceedingly 

 fragrant, densely clothed with a nearly pure white tomentum which 

 completely masks the striae of the stem and extends even to the 

 involucres : leaves 1 to 3 cm. long, about 1 but sometimes nearly 2 mm. 

 wide : inflorescence a rounded often compact cyme : involucre 6 to 

 7 mm. high ; bracts very obtuse, plainly keeled and in 5 distinct ver- 

 tical ranks, woolly but not ciliatc: corolla 6.5 to 8 mm. long; tube 

 more or less cobwebby with loose hairs or these occasionally wanting; 

 lobes ovate, acute, strictly erect, 0.5 to 1 mm. long. 



The type of hololeucus came from Owens Valley, California, 

 whence we now have collections from a number of stations. What 

 appears to be the same form occurs as far south as Antelope Valley 

 and very good hololeucus grows as far north as Pyramid Lake, Nevada, 

 but it does not have a wide east-and-west range. It is confined to loose 

 gravelly or sandy well drained slopes and even in such places it never 

 forms pure stands but occurs as scattered individuals among bushes 

 of other sorts, commonly C. n. gnaph^lodes and Artemisia iridentata. 

 The plants are so white in comparison with these other shrubs that 

 they can be distinguished in the field without difficultv. 



