84 MEMOIRS FROM THE DEPARTMENT OF BOTANY OF COLUMBIA UNIVERSITY 



on very slender pedicels, rather large, yellow ; calyx-lobes lanceolate, the accessory lobes (bractlets) 

 linear. Stamens 20. Styles filiform, nearly terminal."— Watson, /. c. 

 Mexico, State of Chihuahua : C. G. Pringle, No. 1494. 1887. 



67. Potentilla Hookeriana Lehm. 



Pofentilla Hoolrrinna Lehm. Ind. Sem. Hort. Bot. Hamb. 1849 : 10. 1849. 



Lehm. Stirp. Pug. 9: 18; Walp. Ann. 2: 509, Lehm. Rev. Pot. 163. 



Wats. Proc. Am. Acad. 8: 554; I\Iacoun, Cat. Can. PL 137; Rydb. Bull. Torr. 

 Bot. Club, 23 : 302. 



Illustrations: Lehm. Rev. Pot. jj?. 55. Plate J:3,f. 1; dissection of flower,/. ^; 

 pistil,/. 3; stamen,/ 4; fruiting hyi^anthium and calyx,/ 5. 



Stems several from the caudex, 1-2 dm. high, white-tomentose and silky-villous, as- 

 cending, few-leaved. Stipules lanceolate, acute. Leaves with petioles 1-2 cm. long, ternate 

 or occasionall}' with a pair of small extra leaflets, white on both sides, silky-villous above, 

 densely tomentose Ijeneath ; leaflets obovate in outline, about 1 cm. long, deeply cleft to 

 near the midrib into oblong lobes ; middle leaflet short-petioled. Flowers in small 

 dense cymes, about 8-10 mm. in diameter. Hypanthium densely silky-villous, in fruit 

 5 mm. in diameter; bractlets linear, about equalling the lanceolate acute sepals. Petals 

 obcordate, generally a little exceeding the sepals. Stamens 20. 



Dr. "Watson placed this with P. Pcnnsylvrniica on account of the style; this is gland- 

 ular, but scarcely thickened near the base, as it always is in P. Pcnnsylvanica. In 

 haljit it comes nearest to P. rtirca ; and as the style is often glandular in P. villosa and 

 sometimes in P. nivea, it is better to include P. Hookeriana in this group, with which it 

 agrees in other respects. It differs from P. nivca in the more deeply dissected leaves, 

 the smaller flowers, the bractlets, which equal the sepals, and a slightly stricter habit. 

 It is a very rare plant. The only specimens seen are : 



Soshttchcmtn : Bourgeau (Palliser Exp.). 1857-8. 



Montana: Wm. M. Canby, No. 103. 1883 (?). 



Alberta: John Macoun, No. 16735. 1897. 



Rocky Mo nntaln^: Drummond (Lat. 52° 56'). 



68. Potentilla nivea L. 



Potentilla nivea L. Sp. PI. 499. 1753. 



Sp. PL E<1. 2: 715; Willd. Sp. PL 2: 1109; Vahl, FL Dan. 'pl. 1035*; Poir. in 

 Lam. Enc. j\leth. 5 : 600; Persoon, Syn. PL 2 : 56; Nestler, Mon. Pot. 29 and 73 ; Haller, 



