MEMOIRS FROM THE DEPARTMENT OF BOTANY OF 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: 487, 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. arachnoidéa 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. 
tor. Potentilla Coloradensis. 
IntustRATIons: PLATE 52, f. 1; fruiting hypanthium and calyx, f. 2; dissection of 
flower, f. 3; pistil, f. 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 fruit 4-5 mm. in diam- 
eter; bractlets linear-lanceolate, scarcely half as long as the narrowly lanceolate acumi- 
nate sepals. Petals obeordate, 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; C. 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. Cal. 1: 178; Rattan, An. Key W. Coast Bot. 51; Greene, Fl. Fran. 1: 64; 
Coville, Cont. U. 8. Nat. Herb. 4: 95; Rydb. Bull. Torr. Bot. Club 245s 1. 
Stems several from the rootstock, erect-ascending, 1-2.5 dm. high, tomentose, few- 
leaved. Stipules ovate, the lower membranous, brownish and entire, the upper broad, 
