168 REPORT OF AN EXPEDITION DOWN THE 



8 at each joint, verticillate, dull green and pubescent above, clothed with a white 

 wool underneath ; involucres about two lines long, many-flowered, woolly, five- 

 cleft below the middle ; the segments ovate lanceolate, and very acute ; pedicels 

 exserted, jointed close to the flower, glabrous ; bracteoles filiform, plumose ; ex- 

 terior segments of the brownish-red perigonium concave, erect, with a shallow 

 saccate projection on each side of the base ; interior segments one-third as broad 

 as the outer one, emarginate, ovary glabrous, acuminate, crowned with three very 

 short styles ; filaments glabrous ; achenium triquetrous ; seed ovate, acuminate ; 

 cotyledons flat ; radicle elongated, ascending. A very distinct species, but rela- 

 ted to E. Abertiawum. 



E. alatum, (Torr., 1. <:•.;) perenne ; caule erccto subflexuoso folioso, ramis alter- 

 nis erectispaniculatis : foliis spathulatis hirsutis ; pedunculistenninalibus ternis ; 

 involucris solitariis campanulatis 5-fidis : perigoniis glabris, laciniis a;qualibus : 

 acheniis trialatis. On the Zuni river ; September. Root stout and blackish, de- 

 scending to a great depth ; stem 1-3 feet high, arising from a short thick caudex, 

 which is clothed with the remains of leaves. Radical leaves 2-4 inches long, and 

 3-5 lines wide, almost villous, with long hairs, mostly obtuse ; stem leaves 

 much smaller, and gradually diminishing in size upward, all of them erect. 

 Branches solitary and distant, subdivided in a trichotomous manner, each division 

 hearing a single involucre, which is about 2| lines long, and pubescent. Pedicels 

 glabrous, a little exserted, jointed close to the flower ; perigonium not enlarging 

 after flowering ; the segments lanceolate ; filaments glabrous ; ovary oblong, 

 triquetrous, longer than the styles ; achenium nearly four lines long, with three 

 very conspicuous membranaceous wings ; seed ovate, triangular : embrio straight. 



This remarkable species was first detected by Colonel Fremont in upland 

 prairies, at the sources of the Plata, in 1843, and again in 1845 in " Bahia Sa- 

 lada," in the Rocky mountains. Lieutenant Abert found it on the Raton 

 mountains in 184(3. 



E. Jamesii, Benth. in D. C. Prodr. 14, (ined.) E. sericcum, Torr. in Ann. Lye. 

 N. York, 2, p. 241, excl, syn. Head of the Rio Laguna, and on the Zuni moun- 

 tains ; August, September. This is a common species in New Mexico. No. 

 617 Wright, col. 2, is the same. 



E. cermmm, Nutt. PI. Gambel., in Jour. Acad. Phil., (ser. 2,) 1, p. 162. On 

 the Zuni river : September. A small annual species. Captain Stansbury found 



it on Green river, west of the Rocky mountains : Colonel in the South 



Park of the same mountains ; and Lieut. Simpson on the Sierra de Tenu-che. 



E. effusion, Nutt. 1. c: £ ? leptopliyllum, suftrutescens, multicaulis ; ramis 

 erectis foliosis albotomentosis demum glabrescentibus ; foliis angusto-linearibus 

 subglabris ; pedunculiscomposite-trichotomis ; involucris campanulato-tubulosis 

 pauci-(sub 6)-floristruncatis obscure quinquedentatis : perigoniis glabris, laciniis 

 obovatis rcqualibus. Rio Zuni : September. About ten inches high ; stems nu- 

 merous from a ligneous base, slender, leafy to the peduncles ; leaves about an 

 inch long, and scarcely a line wide ; in the dry state revolute on the margin, nearly 

 glabrous. Peduncles many times trichotomous, forming a compound fastigiate 



