[taxon report][distribution map][all photos][line drawing]
(Sierra Blanca cinquefoil)
Scientific Name: Potentilla sierrae-blancae Wooton & Rydberg
Vernacular Name: Sierra Blanca cinquefoil
R-E-D Code: 2-1-3
Description: Perennial herb to 8 cm tall; stems and rootstocks numerous, short, and almost matted, appearing caespitose; leaves digitately 5-foliate; leaflets divided terminally into three lobes; leaflet bases narrowly cuneate; midvein of leaflets raised on lower surface; lateral veins seen as faint lines on lower surface and impressed to some degree on upper surface; leaflets with ciliate margins; cilia on leaf margins up to 2.0 mm long, remote; petioles to 35 mm long, often bearing scattered cilia; largest leaflets to 20 mm long; flowering stems occasionally branched from lower of usually two nodes; flowers solitary at end of peduncle 10-35 mm long; peduncles and lower parts of flowering stem usually villous; petals 5, yellow, about 7 mm long; calyx villous; outer series of 5 bractlets narrowly oblong and obtuse, sparsely long-villous, about 3 mm long, 1 mm wide, with thin reddish margins; sepals 4-4.5 mm long, sparsely long-villous, broad at base, acute at tip; margins scarious in basal 1/3 of each sepal, thin and reddish in distal 2/3; styles terminal. Flowers in June and July.
Similar Species: This species is easily separated from most in the genus by its short habit and narrow, 3-toothed leaflets. The allopatric Potentilla bicrinata also has 3-toothed leaflets, but they are wider and tomentose on the lower surface.
Distribution: New Mexico, southern Lincoln and northern Otero counties, White Mountains.
Habitat: Open windswept crests of ridges and mountain tops on igneous rock substrate with thin soil at 3,350-3,660 m (11,000-12,000 ft); occasionally found on igneous cliffs and outcrops in canyons as low as 2,440 m (8,000 ft).
Remarks: The species occupies a niche where little else can grow. It forms a ground cover on almost barren ridges that are subject to high winds and extremes of temperature. The density of plants can be up to 15/m.
Conservation Considerations: This plant is not significantly threatened by current land uses within its habitat.
Important Literature (*Illustration):
*New Mexico Native Plants Protection Advisory Committee. 1984. A handbook of rare and endemic plants of New Mexico. University of New Mexico Press, Albuquerque.
*Wooton, E.O. and P.A. Rydberg. 1898. [Description of Potentilla sierrae-blancae]. Memoirs from the Department of Botany of Columbia University 2:57.
Information Compiled By:
Richard D. Worthington, 1999