Ivesia rhypara is a species of flowering plant in the rose family known by the common name grimy mousetail, or grimy ivesia. It is native to Oregon and Nevada in the United States. This perennial herb grows from woody roots and a brancing caudex. It has hairy, overlapping, compound basal leaves and stems up to 15 centimeters long. At the ends of the stems are clustered white or pale yellow flowers. Blooming occurs in May through October. The plant gets the name rhypara ("grimy" in Greek) both from its dusty appearance and from its discoverer, James W. Grimes.