GRAY AND BOOKEB ON THE ROCKY MOUNTAIN FLORA. 23 



dance along the dr j valleys, often accompanied by Tetradymia canescens ; 

 but upon the gravelly toot hills the smaller Bigelovia Douglasii is much 

 more frequent." 



One or two names arc changed in copying so as to conform to the 

 more recent nomenclature. Eurotia lanata, though it happens not to 

 come into the above extract, is anion- the commonest of those plants, 

 and is one of the widest in range. Borne Astragali, various Eriogona and 

 Giliu. also several PhaceUcB and Oenothera, would be next in promi- 

 nence, the Eriogona much the most so. But the peculiarity of the 

 basin flora lies as much in the absence of other genera which charac- 

 terize adjacent districts as in the ubiquity of those which have been 

 mentioned. 



The genera peculiar, or nearly so, to the Great Basin proper and its 

 holders are chiefly — 



1'hysaria. a genus which was confounded on mere habit with Vesicaria, 

 belonging to the foot-hills rather than to the valleys, the principal species 

 extending around the whole limits of the region, a peculiar one at the 

 north and another at the south. 



Phtysi)crmum. Hook., a little Cruciferous annual of the western 

 border. 



Pwshia, DC. a lb>>aceous shrub, already mentioned. 



Trioardia and Conanthus, of S. Watson, Hydrophyllaceous herbs, the 

 latter close to Xama. the former a peculiar genus. 



>-t<:s. Watson, a rather obscure Solanaceous herb of Western 

 da. 



EtirophUa, Watson, an Amarantaceous herb of alkaline soil. 



•yia. Hook., a Chenopodiaceous undershrub, already enumerated as 

 OJM <>i" the most characteristic of the desert plants. (Sarcotatu* would 

 go with it. except that it crosses the Uocky Mountains and abounds on 

 tht upper waters of the Missouri, where it was first known, being the 

 Pu py Thorn of Lewis and Clark.) 



1I> rmidiumj Watson, a Xyctagineous perennial of the western edge of 

 the basin, intermediate between BougaiinviUea and Mirabilis. 



Cxytheca, Xutt., an offshoot of the great genus Eriogonum. 



Tetradymia^ DO., characteristic Bhrubby Senecioneous Composite of 

 two or three species, which slightly overpass the borders of the basin. 

 ptopleura, Eaton, of two Bpecies, and Anisoooma y Gray, j i' one. de- 

 ■d < /ichoraceous annuals or biennials. 



Chastadelpha^ BlepharipappuSj and Rigiopappus, each of a Bingle spe< 

 tmdPsathyrotesot two, southern in range, also Composite. 



Their i>. besides, Caulanthus of 8. Watson, of two or three very char- 

 but some Caliioraian, and the genus is only 

 artificially distinguished from StreptanikMs, species of which reacb the 

 "li the one hand and Missouri to Texas on the other. 



/ . - Watson, is a peculiar genus of grasses, one species pe- 



culiar to the basin, another to the southeastern part of New M< 



