48 MEMOIRS FROM THE DEPARTMENT OF BOTANY OF COLUMBIA UNIVERSITY 
Rydberg, Cont. U.S. Nat. Herb. 3: 157; Bull. Torr. Bot. Club, 23: 262; FI. Neb. 
91: 17: Britton & Brown, Ill. Fl. 2: 212: 
Potentilla rivalis var. pentandra Wats. Proc. Am. Aead. 8: 553. 1873. 
Wats. & Coult. in Gray, Man. Ed. 6: 159. 
Iutusrrations: Lehm. Rev. Pot. pl. 62; > 2s Britton & Brown, Ill. Fl. 2: f. 1923. 
PEATE dots 25 dissection of flower, f. 2; pistil, f. 3; stamen, f. 4; fruiting hypanthium 
and calyx, f. 5. 
Stems stout, very leafy, 3-7 dm. high, erect, often tinged with brown, finely hirsute 
and much branched above. Stipules broadly ovate-acuminate, 1-2 em. long, deeply 
toothed. Lower leaves pedately 5-foliolate, or 3-foliolate with the lateral leaflets 2-cleft, 
with hirsute petioles 83-8 em. long; the uppermost 3-foliolate and very short-petioled. Leaf- 
lets 2-10 em. long, oblong to oblanceolate or cuneate, deeply serrate. Cyme very dense 
and leafy, in age, as a rule, flat-topped. Flowers on short hirsute pedicels, less than 5 
mm. in diameter. Cup sparingly hirsute and finely pubescent, in age about 5 mm. in 
diameter. Bractlets oblong, acute, nearly as long as the ovate acute sepals but much 
narrower. Petals pale yellow, obovate, scarcely half as long as the sepals. Stamens 
seldom more than 5, very small, with didymous anthers. Pistils exceedingly numerous; 
style terminal, short-fusiform and glandular below. Achenes smooth, brownish. 
P. pentandra is characterized by its leaves, which are pedately 5-foliolate or 3-foliolate 
with the lateral leaflets cleft to near the base, by the exceedingly numerous small flowers 
in a somewhat flat-topped cyme, by remarkably small petals and generally only five 
stamens. It is often as stout as P. Monspeliensis and more bushy. Its range is from 
Missouri and Iowa to Alberta and Arkansas. Specimens studied: 
Missouri: G. Engelmann, No. 970, 1835 (type); B. F. Bush; 1893, No. 280, 1895. 
Towa: Witcheock; J. C. Arthur, 1874. 
Nebraska: H. J. Webber, 1888; P. A. Rydberg, No. 1819, 1893; Fred. Clements, 
No. 2655, 1893; C. E. Bessey, 1890. 
North Dakota: E. L. Greene, 1899. 
Minnesota: C. A. Ballard, No. 252. 
Manitoba: Macoun, No. 12580, 1896. 
Alberta: Macoun, No. 626, 1885. 
