Senecio werneriifolius Packera werneriifolia, known by the common names alpine rock butterweed and hoary groundsel, is a species of flowering plant in the aster family.

It is native to the western United States in the Sierra Nevada mountain habitat in subalpine and alpine climates, including forests and barren talus.

It grows up to about 15 centimeters tall from a basal rosette of thick, linear or oval leaves a few centimeters long; leaf morphology varies from the western to the eastern regions of the plant's range.

The basal leaves are woolly, white to greenish and tufted with smooth and nearly entire (smooth-edged) leaf margins and multiple 4 to 8 inches (10 to 20 cm), nearly leafless stems bearing 1-6 flower heads.

[1]: 219–220 It is a low growing perennial plant that can be found growing in the severe conditions of the high northern and central Sierra Nevada range, from 10,000 to 13,000 feet (3,000 to 4,000 m) in elevation.