MEMOIRS FROM THE DEPARTMENT OF BOTANY OF COLUMBIA UNIVERSITY 103 



86. Potentilla tenerrima Rydb. 



Potentilla tenerrima Rydberg, Bull. Torr. Bot. Club, 23: 398. 1896. 



Illustrations: Bull. Torr. Bot. Club, 23: pi 275, f. 1-5. Plate 4^, /. 1; fruit- 

 ing hypanthium and calyx,/. 2; dissection of flower,/. 3; pistil,/ 4; stamen,/ 5. 



Tufted from a perennial root ; stems many, very slender, generally tinged with red, 

 1-1.5 dm. high, sparingly strigose ; stipules linear-lanceolate, acuminate, about 1 cm. long, 

 the lower scarious and brown. Leaves digitately 3-foliolate, with a pair of smaller leaflets 

 below, or' pinnate with 2 pairs of leaflets and the terminal leaflet sessile, finely silky 

 and a little grayish tomentulose beneath ; leaflets obovate or oblanceolate in outhne, 

 divided to near the midrid into hnear acute segments. Flowers on slender pedicels, nearly 

 1 cm. in diameter. Hypanthium silky-strigose, in fruit .5 cm. in diameter; bractlets 

 linear, acute, very little shorter than the narrowly lanceolate sepals. Petals obovate, 

 slightly retuse, a little exceeding the sepals. Stamens about 20. Style filiform, nearly 

 terminal. Achenes smooth. 



This resembles a very slender form of P. rnbricaulis, but the plant is usually more 

 erect. The segments of the leafiets are also much narrower, as also the bractlets and 

 sepals, which are narrower than in any other North American species. 



Colorado: Brandegee, No. 950, 1874 (from Bergen's Park, type); Hall and Harbour, 

 No. 160 (in part, in the Harvard Herbarium) ; L. H. Pammel, 1895. 



87. Potentilla saximontana Rydberg. 



Potentilla saximontana Rydb. Bull. Torr. Bot. Club, 23: 399. 1896. 



Potentilla nivea Eothrock, Rep. U. S. Geogr. Surv. 6: 113. Name and locality only. 

 1878. Not L. 



Illustrations: Bull. Torr. Bot. Club, 23: j??. 277, f. 6-10. Plate 43, f. 6 ; fruit- 

 ing hypanthium and calyx,/ 7 ; dissection of flower,/ 8 ; stamen,/. 9 ; pistil,/ 10. 



Densely cespitose ; stems several, 1-3-flowered, less than 5 cm. long, silky pubescent. 

 Basal leaves numerous, pinnate with 2-3 often approximate pairs of leaflets, silky pubes- 

 cent and somewhat tomentose beneath, short-petioled ; leaflets deeply dissected into ob- 

 long obtuse or acute segments. Flowers about 1 cm. in diameter. Hypanthium densely 

 silky ; bractlets oblong, obtuse, shorter than the broadly ovate-triangular sepals. Petals 

 broadly obcordate, much longer than the sepals. Stamens about 20. Style nearly 

 terminal, about equalling the smooth achene. 



It somewhat resembles P. ruhricaulis, but is still more cespitose, has much broader 

 sepals and leaves, which have mostly much shorter petioles. The leaves are some- 



