Arctic butterbur

Petasites frigidus is a stoloniferous perennial herb of the Asteraceae family growing 10-50 cm tall from extensive creeping rhizomes, often forming large colonies in suitable habitats. Flowering stems are erect, stout, fleshy, hollow and clothed in scale-like bracts, appearing before or with the leaves in early spring. Basal leaves are long-petiolate and arise after the flowers; the blade is broadly triangular to reniform-orbicular, 5-25 cm wide, palmately three- to seven-lobed or shallowly toothed in some varieties, dark green and glabrous to thinly cobwebby above and densely white-tomentose beneath. The inflorescence is a corymbose to short-racemose cluster of several to many heads at the stem apex; each head is 6-12 mm across with an involucre of one to two rows of green to purplish bracts. Heads are typically subdioecious: pistillate heads bear numerous slender white to pinkish ray-like florets and sterile central disc florets, while staminate heads contain functionally male tubular florets with abortive ovaries. Achenes are small, ribbed and bear a pappus of soft white bristles. Native to wet meadows, streamsides, tundra, bogs and damp forest of subarctic and boreal North America.