to Oregon and California. 89 



The route along the North Fork of the Platte afforded 

 some of the best plants in the collection. The /S'enecio rapi- 

 folia (Nuttall) occurred in many places quite to the Sweet 

 Water. Lippia (Zapant'a) cuneifolia, (Torrey, in James's 

 Plants, only known here from Dr. James's collection,) — Cerco- 

 carpus parvifolius Nvtt. Eriogonum parvifolium, and E. 

 csespitosum Niitt. Shepherdid argentea Nutt. ; and Ge- 

 ranium Fremontii a new species, (near the Red Buttes,) 

 were found in this part of the journey. In saline soils, on the 

 Upper Platte, near the mouth of the Sweet Water, were col- 

 lected several interesting Chenopodiace^, one of which was 

 first discovered by Dr. James, in Long's Expedition ; and al- 

 though it was considered a new genus, I did not describe it, 

 owing to the want of the ripe fruit. It is the plant, doubt- 

 fully referred, by Hooker, in his Florea Boreali Americana, 

 to Batis. He had seen the male tlowers only. As it is cer- 

 tainly a new genus, I have dedicated it to ihe excellent com- 

 mander of the expedition, as a well merited compliment, for 

 the services he has rendered North American Botany. * * 



* * * Along the Sweet Water, many interesting plants 

 were collected, as may be seen by an examination of the 

 Catalogue. I would, however, mention the curious ffi'nothe- 

 ra Nuttallii (Tor. & Gr.) Eurotia Janata Mocq : (Di 

 Otis lanata Ph.) which seems to be distinct from E. ceratoi- 

 des; Thermopsis montana Nuit. Gilia pulchella Doiigl. 

 iSenecio spartioides Tor. c5* Gr.., a new species ; and four 

 or five species of wild currants, (i2i6e5 irriguum, Dougl.&Lc.) 

 Near the mouth of the Sweet Water, was found the Plan- 

 tago eirophora 7 or., a species first described in Dr. 

 James's Rocky Mountain Plants. On the upper part, and 

 near the dividing ridge, were collected several species of Cas- 

 tilleja; Pentstemon micrantha Nvtt.; several Gentianr ; the 

 pretty little Androsace occidentalis Nvtt. ; Solidago i;:cana 

 Tor. <^* Gr. — and two species of Eriogonum; one of which 

 was new. 



On the eighth of August, the exploring party crossed the 

 dividing ridge or pass; and found the soil of the plains, at 

 the foot of the mountains, on the western side, to be sandy. 

 From Laramie's Fork to this point, different species of Arte- 

 mesia were the characteristic and prevailing plants; occupy- 



VOL. XII. NO. III. 12 



