Ivesia santolinoides A. Gray

Stellariopsis santolinoides (A. Gray) Rydb. Mem. Dep. Bot
Columbia Univ. 2 : 155. 1898.
Ivesia santolinoides A. Gray, Proc. Am. Acad. 6: 531. 1865. Potenlilla santolinoides Greene, Pittonia 1 : 106. 1887.
Perennial, with a deep root, not very thick, crowned with a short erect caudex, which is densely covered with hairy scales; stems several, erect, much branched, more or less silky-villous on the lower portion with long white spreading or reflexed hairs ; stipules ovate, 5 mm. or less, often divided ; basal leaves numerous, 3-10 cm. long, densely whitesilky, terete and worm-like from the numerous minute crowded leaflets ; stem-leaves similar, but smaller; cyme intricately branched into filiform branches and very slender pedicels 1-2 cm. long ; hypanthium finely puberulent, saucershaped, in fruit 3 mm. in diameter ; bractlets ovate, minute, about one fourth the length of the ovate sepals, which are 1.5 mm. long ; petals white, broadly obovate or orbicular, twice as long as the sepals.
Type ix>CALiTy : Sierra Nevada, California.
Distribution : Sierra Nevada and San Bernardino Mountains, California.

Ivesia santolinoides is a species of flowering plant in the rose family known by the common names silver mousetail, stellariopsis, Sierra mousetail and mousetail ivesia. It is endemic to California where it grows in several mountain ranges, including the Sierra Nevada and Transverse Ranges.

This is a perennial herb which can be somewhat different in appearance from many other mousetails. Each leaf is made up of many leaflets but they are tiny and overlap tightly to form a woolly, taillike, cylindrical leaf up to 10 centimeters long. The erect, naked stem reaches up to 40 centimeters in height and bears an inflorescence of flowers. Each flower is up to 8 millimeters wide and has large, round white petals above the much smaller, pointed sepals. There are 15 stamens and a single pistil.