Antennaria dioica

Dioecious. Plants 3-10 cm. Stolons 2-5 cm. Basal leaves 1-nerved, spatulate or rhombic-spatulate, 3-18 × 3-6 mm, tips mucronate, abaxial faces gray-tomentose, adaxial green-glabrous. Cauline leaves linear, 7-13 mm, not flagged (apices acute). Heads 3-7 in corymbiform arrays. Involucres: staminate 5-6.5 mm; pistillate 5-7 mm. Phyllaries distally dark pink to light pink or white. Corollas: staminate 3-4 mm; pistillate 4-5 mm. Cypselae 0.5-1 mm, papillate; pappi: staminate 3.5-4.5 mm; pistillate 5-6 mm. 2n = 28.

Flowering summer. Dry slopes on tundra; 0-600 m; Alaska (Aleutian Islands); Eurasia.

Antennaria dioica ranges from the British Isles to Japan and into the Aleutian Islands (R. J. Bayer 2000). It is characterized by glabrous adaxial leaf faces and distally pink or white phyllaries. The circumscription of A. dioica in North America has long been debated; A. marginata of southwestern states bears a remarkable similarity to A. dioica. DNA sequence data (Bayer et al. 1996) indicate that the two taxa are not sisters; they are only distantly related. They are allopatric. Antennaria dioica may be a sexual progenitor of the A. parvifolia complex.