to the Rocky Mountains. 241 



387. Rumex venosus, Purshjl. ii. p. 733. Nutt. gen. 

 i. p. 240. Sandy plains on the upper part of the Platte. 



38S. Eriogonum sericeum, Purshfl. i. p. 277. E. flavum, 

 Nutt. gen. i. p. 26. Ejusd.jour. acad. Phil. i. p. 33. 



Sources of the Platte. 



3S9. E. annuum, n. sp. Nutt. mss. Near the Rocky 

 Mountains. Found also on the Arkansa by Mr. Nuttall. 

 Root annual ! 



390. E. tenellum, caule dichotomo, nudo, gracili, gla- 

 berrimo ; ramis elongatis, apicefasciculum florum gerentibus ; 

 floribus minutissimis ; calycis laciniis subrotundis, obtusis, 

 glabris ; foliis ovatis, subcordatis, subtus (junioribus utrinque) 

 niveo-tomentosls, supra pubescentibus. 



Desc. Root perennial, thick, descending-. Stern cespitose, only leafy 

 about the root, branched ; branches very slender and smooth, terete. 

 Leaves petiolate, scarcely three-fourths of an inch long; the older ones 

 subcordate, white and very tomentose beneath, pubescent and greenish 

 above ; young ones white and densely tomentose on both sides. Flowers 

 very minute, growing in solitary fasciculi at the extremity of the almost 

 fil.form brandies. Involucrum smooth, turbinate, 10-12-flowered ; border 

 6-6-toothed. Calyx very smooth ; segments roundish, unequal. 



Hab. With the preceding. 



Obs. Scarcely a foot high. Involucrum sometimes pro- 

 liferous. 



391. E. umbellatum, caule nudo, simplici ; pedunculis 

 elongatis (sub-senis)umbellatis, apice involucrum singulum ge- 

 rentibus ; calycibus glabris ; laciniis obovatis, basi angusta- 

 tis, obtusis ; foliis obovato-spathulatis, subtus lanuginosis, 

 supra glabriusculis. 



Desc Perennial, herbaceous, cespitose. Caadex divided at the base 

 into several branches ; most of the branches short, bearing fasciculi of 

 leaves at the extremity, one of them elongated and resembling a scape; 

 covered with a copious loose tomentum. .Leases obovate-spathulate, about 

 an inch long, and less than half an inch broad, white-tomentose beneath, 

 smoothish above. Flowering stem a span high, bearing a simple umbel at the 

 extremity. Peduncles or rays an inch and a half long, woolly, thick, fur- 

 nished with several oblong-lanceolate leaves at the base. Involucrum 



