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. Description It is a perennial herb which is usually small but is otherwise variable in appearance. 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 , nearly leafless stems bearing 1-6 flower heads. The inflorescence bears a single flower head or a cluster of a few heads and may be nearly hairless to quite woolly. The flower head contains up to 40 yellow disc florets, and usually either 8 or 13 yellow ray florets, though these are sometimes absent. It blooms in July to August. Habitat and range 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 in elevation. References External links Jepson Manual Treatment of Packera werneriifolia USDA Plants Profile for Packera werneriifolia Flora of North America Southwest Colorado Wildflowers UC CalPhotos gallery of Packera werneriifolia werneriifolia Alpine flora Flora of the Western United States Flora of California Flora of Colorado Flora of the Sierra Nevada (United States) Flora of the Rocky Mountains Taxa named by Asa Gray Flora without expected TNC conservation status