Tas. 6560. 
POTENTILLA (Ivesra) uneurounata. : 
Native of California. 
Nat. Ord. Rosacem.—Tribe PorentinieR. 
Genus PoTENTILLa, Linn.; (Benth. et Hook. f. Gen. Pl. vol. i. p. 620.) 
Porentinia (Ivesia) wnguiculata; sericeo-villosa, caule gracili sparse folioso 
superne paniculatim ramoso, foliis radicalibus anguste lineari-elongatis ob folia 
imbricata cylindraceis, foliis sessilibus 3-foliolatis, foliolis elliptico-lanceolatis 
acutis integerrimis, floribus laxe paniculatis, calycis tubo campanulato lobis 
ovatis acuminatis, petalis orbiculatis calyce paulo longioribus albis ungue sub- 
elongata, staminibus 2-seriatis numerosis, filamentis filiformibus, carpellis 
3-8 glabris, stylo gracili. 
Ivesta unguiculata, Gray in Proc. Amer. Acad. vol. vii. p. 339; S. Watson, 1. ec. 
448, et in Bot. Calif. vol, i. p. 183. 
> * 
as 
A very delicate silvery plant, with pearly-white flowers, 
a native of the famous Yosemite Valley in California, 
where it grows in meadows at an elevation of 8000 feet 
above the sea-level. In a young state and in dry weather 
it forms a really charming herbaceous border- or rock-plant, 
but when dashed by the rains of an English summer (an 
ordeal it is not exposed to in its native country), it presents 
a miserable and draggled appearance, its beautiful leaves 
being sometimes beaten down and almost buried in the 
soil. It belongs to a section of Potentilla which has been 
erected into a gertus under the name of Ivesia, consisting 
of nearly a dozen species, natives of the mountains of 
Western North America, with usually small imbricating 
_ leaflets that give the leaf more or less of a cylindrical 
form; this character, combined with others appertaining 
to the first discovered species, appeared to suffice to 
establish the genus as distinct from Potentilla and Horkelia. 
Subsequent discoveries, however, have invalidated the 
claims of Ivesia, and it was reduced to Potentilla in the 
“Genera Plantarum,” respecting which view Dr. Gray says 
under Horkelia Bolanderi (Proc. Amer. Acad. vol. vii. 
MAY Isr, 1881. ” 
