8 Rhodora [JANUARY 
while luxuriant plants have leaves 4.3 dm. long, the terminal leaflet 
5.5 сш. in length. Argentina subarctica Rydberg, judging from speci- 
mens in the Gray Herbarium named by Dr. Rydberg, is transitional 
between well developed Potentilla pacifica and its most dwarfed state. 
As interpreted by the writer the members of this group in eastern 
America should be classified as follows. 
* Achene thiek-ovoid to subglobose, more or less corky, dorsally suleate: 
stolons, peduncles, petioles, and rhachises more or less pubescent with ascend- 
ing or loosely spreading hairs: leaflets silvery-silky beneath, at least the 
younger lustrous. 
P. ANSERINA L. Leaflets green and glabrous or glabrate above: 
bractlets often cleft.— Sp. 495 (1753). P. Argentina Huds. Fl. Ang. 
195 (1762). Argentina vulgaris Lam. Fl. Fr. iii. 119 (1778). P. 
Anserina a vulgaris Hayne, Arzneigew. iv. 31 (1816) according to 
Wolf, Mon. Pot. 672 (1908). P. Anserina a discolor Wallr. Sched. 
Crit. i. 236 (1822). Argentina Anserina Rydb. Mem. Dept. Bot. 
Columbia Univ. ii. 159 (1898).— Widely distributed in northern regions. 
In America extending south, chiefly in gravelly or sandy soil, to Prince 
Edward Island, the St. John Valley of New Brunswick and Maine, 
Lake Champlain, western New York, northern Indiana, central 
Illinois, lowa, New Mexico, and southern California. 
Var. SERICEA Hayne. Leaflets silvery-sericeous on both surfaces. 
— Arzneigew. iv. 31 (1816) according to Wolf, Mon. Pot. 672, 673 
(1908). P. Anserina B. concolor Wallr. Sched. Crit. 1. 236 (1822). 
P. Anserina B. holosericea Gaudin, Fl. Helvet. iii. 406 (1828). P. 
Anserina, a argentea Neilr. Fl. N. Österr. 908 (1859). Р. Anserina 
a. unicolor Schur, En. pl. Transs. 189 (1866). P. sericea Zimmeter, 
Eur. Art Pot. 6 (1884), acc. to Wolf. P. concolor Zimmeter, Bot. Kal. 
66 (1887) ace. to Wolf. Argentina Anserina concolor Rydb. Mem. 
Dept. Bot. Columbia Univ. ii. 160 (1898). A. argentea Rydb. Bull. 
Torr. Bot. Cl. xx. iii. 143 (1906).— Of similar distribution; in the 
eastern states and Canada often growing with or near the typical form 
of the species; in the more arid regions of North America generally 
with thickish leaves. 
* * Achene laterally compressed, firm, rounded on the back, not suleate: 
stolons, peduncles, petioles, and rhachises glabrous or glabrate: leaflets white- 
tomentose beneath with opaque hairs (slightly if at all sericeous) or glabrate. 
+ Calyx and lower surfaces of the interruptedly pinnate leaves white- 
tomentose. 
P. РАС1Ё1СА Howell. Leaves 0.3-5 dm. long, with 7-31 oblong, 
oblanceolate, or obovate leaflets: bractlets usually simple.— Fl. N. 
W. Am. i. 179 (1898). Р. Anserina groenlandica Tratt. Ros. Monog. 
