Ivesia argyrocoma is a species of flowering plant in the rose family known by the common name silverhair mousetail. It is native to the San Bernardino Mountains of southwestern San Bernardino County, California. A population is also known from Baja California in Mexico; this population may or may not be distinct and further study is needed. This is a small perennial herb producing a clump of fuzzy reddish naked stems that grow horizontal to the ground and a number of tail-like hairy leaves which grow erect and may curl or droop. The stems are 10 to 20 centimeters long. Each leaf is a nearly cylindrical strip of tightly overlapping leaflets arranged around a central rachis up to 8 centimeters long. The leaflets are green and covered in a dense coat of shiny silver hairs. Most of the leaves