318 PLANTS NOV^ THURBERIAN^. 



furnished with a depressed and concave gland. The two partial petioles are about the 

 length of the main petiole, and are terminated by a single pair of leaflets, of a thick 

 and firm texture, and of an extraordinary size for this genus, being often an inch and 

 a half in length, and H to 2 inches in breadth, and with their strong and salient 

 nerves, as well as their branching veins, equally conspicuous on both sides. The 

 foliage, inflorescence, and general habit of the plant would refer it rather to Pitheco- 

 lohium than to any other genus. But the stamens are ochroleucous and not monadel- 

 phous : they are barely three lines long, and less than twice the length of the corolla. 

 The tube of the latter is glabrous Avhere it is covered by the somewhat turbinate and 

 five-toothed calyx. Ovary oval-oblong, short-stipitate, glabrous, containing several 

 ovules. Unless the fruit furnishes some peculiar characters, the plant must remain in 

 the genus Acacia. 



PoTEXTiLLA Thurberi (sp. nov.) : multiceps, viridis, subpubescens ; caulibus e rhi- 

 zomate crasso adscendentibus (pedalibus et ultra) plurifloris ; foliis glabellis membra- 

 naceis, radicalibus digitatis .5 - 7-foliolatis, petiolo patentim piloso, foliolis sessilibus 

 obovato-oblongis grosse serratis, caulinis parvulis subsessilibus trifoliolatis ; stipulis 

 2 - 3-dentatis ; floribus laxe c)-moso-paniculatis longiuscule pedicellatis ; segmentis 

 calycinis accessoriis oblongo-lanceolatis sepala sequantibus pctalis atro-sanguineis ob- 

 cordato-rotundis vel emarginatis paullo brevioribus ; receptaculo conico breviter vil- 

 loso ; acheniis glabris vix rugulosis ; stylo fere terminali. — Near Santa Rita del Cobre, 

 New Mexico; August, 1851. — This remarkable species, which appears not to have 

 been seen either by Mr. Wright or Dr. Bigelow, — who largely collected in the same 

 region, — is one of those which invalidate the genus Comarum. It is manifestly allied 

 to the Mexican P. comaroides, of Humboldt, though very distinct from it, and belongs 

 to the Herbacece, Multicipites, Ser. 2, Multiflorce, Rectce, of Lehmann's recent arrange- 

 ment. Petioles of the radical leaves about 3 inches long ; the leaflets H to 2 inches 

 long, green both sides, coarsely and obtusely serrate almost to the base. Leaflets of 

 the lowest cauline leaves nearly similar ; the others with fewer teeth ; the uppermost 

 reduced to small and cuneate three-toothed bracts. Inflorescence minutely pubescent. 

 Pedicels 5 to 12 lines long. Calyx sparingly pilose. Petals about 3 lines long. Sta- 

 mens 25 to 30, with slender and subulate filaments. Disc nearly as in P. ( Comarum) 

 palusti-is. Receptacle enlarged in fruit, and scrobiculate.* 



* Specimens of this striking Potentilla have just come to hand, collected by Dr. Henrjs of the United States 

 Army, on the Kio Mimbres, and by Dr. Bigelow, I believe from the mountains east of the Rio Grande. 



