17b. Antennaria howellii Greene subsp. howellii
Antennaria callilepis Greene; A. exima Greene
Plants 15–30 cm. Stolons 1–4 cm. Basal leaves 1–3-nerved, spatulate to oblanceolate, 25–40 × 9–12 mm, tips mucronate, faces abaxially tomentose, adaxially green-glabrous. Cauline leaves linear, 20–40 mm, not flagged. Heads 5–12 in corymbiform arrays. Involucres: staminate unknown; pistillate 6–7.5 mm. Phyllaries distally light brown or white. Corollas: pistillate 5–6 mm. Cypselae 1.5–2 mm, notably papillate; pappi: pistillate 6–8 mm. 2n = 56, 84, 140 (under A. neodioica).
Flowering mid spring–early summer. Pastures, dry fields, openings in deciduous woodlands and coniferous forests. and rock barrens; 0–2200 m; Alta., B.C., Ont., Sask., Yukon; Calif., Colo., Idaho, Minn., Mont., Oreg., S.Dak., Utah, Wash., Wis., Wyo.
Subspecies howellii is most common in the western half of the range of Antennaria howellii. Based on morphology, this group of apomicts is closely related to A. racemosa of the northern Rockies (R. J. Bayer 1985) and, perhaps, to A. marginata of the southern Rockies.