King's Mousetail

Ivesia eremica (Coville) Rydberg
Poientilla eremica Coville, Proc. Biol. See. Wash. 7 : 76. 1892.
Polentilla Kingii inceria M. E. Jones, Zee 4 : 277. 1893,
Horkelia eremica Rydb. Mem. Dep. Bot. Columbia Univ. 2 : 147. 1898.
Perennial, with a deep, thick, woody root, crowned by a cespitose caudex ; stems several, decumbent or ascending, finely gra3dsh-puberulent or glabrate, 2-4 dm. high, simple, somewhat leafy ; stipules ovate, 5 cm. long or less, entire ; basal leaves very numerous, grayish hirsute-ciliolate or glabrate, nearly terete and worm-like, with densely crowded ovate leaflets 2-3 mm. long, which, however, are evidently two-ranked ; stem-leaves similar ; cyme narrow, with erect branches, the pedicels 5-15 mm. long; hypanthium puberulent or glabrate, saucer-shaped, 3 mm. broad; bractlets ovate or oblong, about a third the length of the lanceolate sepals, which are 3 mm. long ; petals white, obovate, exceeding the sepals by one half, rounded at the apex; stamens 20 ; filaments filiform.
Type locality : Watkins' Ranch, Ash Meadow, Nye County, Nevada.
Distribution : Desert regions of Nevada.

Ivesia kingii S. Wats. Bot. King's Expl. 91. 1871
Poientilla Kingii Greene, Pittonia 1 : 105. 1887.
Horkelia Kingii Rydb. Mpm. Dep. Bot. Columbia Univ. 2 : 148. 1898.
Ivesia pallida Greene ; Rydb. Mem. Dep, Bot. Columbia Univ. 2 : 148, as a synonym. 1898.
Perennial, with a thick, deep and woody root, crowned with a very short erect caudex ; stems several, leafy, glabrous, prostrate, 2-A dm. long; stipules ovate, 5-8 mm. long, entire ; basal leaves numerous, glabrous and shining, about 5 cm. long, pinnate, with 2025 pairs of crowded leaflets, glabrous ; leaflets 3-5 mm. long, divided to the base into 2-4 ovate or oblong segments; cyme narrow, with slender pedicels 5-10 mm. long; hypanthium saucer -shaped, in fruit 3-4 mm. in diameter; bractlets ovate or lanceolate, about half as long as the broadly lanceolate sepals, which are 2 mm. long; petals white, obovate or broadly spatulate, much exceeding the sepals ; stamens 20 ; filaments filiform.
Type locality : Monitor Valley, Nevada.
Distribution : Desert regions of Nevada and western Utah.

Ivesia kingii, sometimes reclassified as Potentilla kingii, is a species of flowering plant known by the common name King's mousetail.

It is native to the southwestern United States, where it is known from eastern California, Nevada, and Utah.

One variety of this species, var. eremica, is endemic to Ash Meadows in the Amargosa Desert, in Nye County, Nevada, on the California-Nevada border. It is federally listed as a threatened species of the United States.