MEMOIRS FROM THE DEPARTMENT OP BOTANY OP COLUMBIA UNIVERSITY 115 



the dry plains from New Mexico to Montana, Assiniboia (and Minnesota ?). Some 

 specimens seem to unite this species with the next. 



Potentilla effusa gossypina Nutt.; Torr & Gray, Fl. N. Am. 1 : 437, 1849, is still un- 

 known. Dr. Hooker, in London Jour. Bot. 6: 219, states that the plant collected by 

 Geyer (No. 637) was labelled by Nuttall P. gossypina. These specimens Dr. Hooker 

 identified as P. arachnoidea Douglas, which is P. Pennsylvanica arachnoidea Lehm. 

 There is no specimen in Nuttall's herbarium at the Academy of Natural Sciences of 

 Philadelphia, nor in the Torrey or the Gray herbaria. 



loi. Potentilla Coloradensis. 



Illustrations : Plate 5S, f. 1 ; fruiting hypanthium and calyx,/. 2 ; dissection of 

 flower, /. 3; pistil, /. 4. 



Stems several from the perennial caudex, rather slender, silky tomentose, in age gla- 

 brate, about 3 dm. high, branched. Lower stipules scarious and brown, covering the 

 caudex, the upper lanceolate, entire. Basal leaves interruptedly and irregularly pinnate ; 

 leaflets 4-6 pairs, finely tomentose, or in age glabrate. Stem leaves mostly ternate, or the 

 upper simple; leaflets cuneate, incisely serrate with triangular acute teeth. Cyme 

 branched with ascending branches. Hypanthium tomentose, in frait 4-5 mm. in diam- 

 eter ; bractlets linear-lanceolate, scarcely half as long as the narrowly lanceolate acumi- 

 nate sepals. Petals obcordate, scarcely exceeding the sepals. Stamens about 20. Pistils 

 10-20. 



This species has been confused with P. effusa, but differs in the more erect, more 

 slender stems, the finer pubescence, the triangular teeth of the leaves and the fewer pis- 

 tils. The following specimens have been examined. . 



Colorado: T. C. Porter, 1872 (South Park); H. N. Patterson, No. 27, 1885 (George- 

 town); H. G. French, 1874 (Boulder); Pammel, 1896; G. F. Baker, No. 10, 1896; 

 Rydberg, 1895; G. E. Osterhout, 1893. 



Wyoming: A. Nelson, Nos. 1368 and 2017, 1895. 



102. Potentilla Breweri Wats. 



Potentilla Breweri Wats. Proc. Am. Acad. 8: 555. 1873. 



Bot. Gal. 1 : 178 ; Eattan, An. Key W. Coast Bot. 51 ; Greene, Fl. Fran. 1 : 64 ; 

 Coville, Cont. U. S. Nat. Herb. 4 : 95 ; Rydb. Bull. Torr. Bot. Club, 24: 1. 



Stems several from the rootstock, erect-ascending, 1-2.5 dm. higb, tomentose, few- 

 leaved. Stipules ovate, the lower membranous, brownish and entire, the upper broad, 



