New Plants from Wyoming. — XI 



By Aves Nelson 



^Potentilla Wyomingensis 



Root deep set and woody : caudex densely caespitose ; its 

 branches thick and closely covered with brown scales (the remains 

 of old leaves) : stems numerous, bearing 1—3 small leaves, pubes- 

 cent, 1.5—2.5 dm. high: leaves crowded on the crown, silky 

 pubescent, more sparsely so on the upper surface, usually some of 

 them glabrate, pinnate, 5-10 cm. long : leaflets 13—19, irregularly 

 disposed on the channelled rachis and with smaller oblong-linear 

 ones interspersed, crowded toward the apex, the lower 3— 5 -fid, the 

 upper with more numerous pinnate segments, the segments oblong 

 to linear : cyme irregular, open, 3-9-flowered, rarely 1 3 ; pedicels 

 spreading, 1-4 cm. long : hypanthium hirsute, in fruit 5-7 mm. 

 in diameter : bractlets small, oblong-linear, much shorter than the 

 ovate-lanceolate sepals : petals yellow, very broadly obovate, re- 

 tusely truncate at summit : stamens 20 : pistils 1 5—20. 



This species belongs to the section Multijugae and finds its 

 affinity with P. pinnatisecta (Wats.) Aven Nelson, though it is a 

 much larger plant with more numerous and much more finely dis- 

 sected leaflets and more spreading habit. It is sub-alpine while 

 P. pinnatisecta is distinctly alpine. 



First collected in fruit only, on a grassy north slope near the 

 highest summits of the Seminole Mountains, by Elias Nelson, July 

 21, 1898, no. 4916. Better specimens secured by the writer in an 

 exactly similar location on Druid Peak, in the Yellowstone Park, 

 July 12, 1899, no. 5781, may be cited as typical of this species. 



* Potentilla jucunda 



Stems usually several, green, obscurely appressed-pubescent 

 rather slender, nearly erect, simple except for the corymbosely- 

 branched, open cyme : stipules lanceolate, acute, entire ; basal 

 leaves several to many, digitately 5-7-foliate, greatly variable in 

 size, on slender petioles, 5-20 cm. long ; leaflets 4-7 cm. long, 

 from narrowly obovate to oblanceolate, coarsely serrate, the teeth 

 extending nearly half way to the midrib, green on both sides, 

 nearly glabrous above, lightly pubescent beneath : stem leaves 

 smaller and shorter petioled, the uppermost sessile with narrow 



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