Dioecious or gynoecious (staminate plants in equal frequency as pistillates or none in populations, respectively). Plants 5-20 cm (stems sometimes stipitate-glandular, especially in dioecious diploids). Stolons 2-7 cm (woolly). Basal leaves 1-3-nerved, spatulate, 15-20 × 4-6 mm, tips mucronate, abaxial faces gray-tomentose, adaxial green-glabrous (margins white woolly). Cauline leaves linear, 7-16 mm, (apices acute) not flagged. Heads 5-8 in corymbiform arrays. Involucres: staminate 4.5-7 mm; pistillate 5-7(-9) mm. Phyllaries (relatively wide), distally white (apices acuminate). Corollas: staminate 3-5 mm; pistillate 4.5-6.5 mm. Cypselae 0.8-2 mm, glabrous or slightly papillate; pappi: staminate 3.5-5.5 mm; pistillate 5.5-8.5 mm. 2n = 28, 56, 84, 112, 140.

Flowering summer. Moist forests, slopes and tops of ridges under Douglas fir, ponderosa pine, Engelmann spruce or Gambel oaks, openings in the forests; 1500-2900 m; Ariz., Calif., Colo., N.Mex., Tex.; Mexico (Chihuahua, Coahuila).

Antennaria marginata has rims of white hairs (from the abaxial faces) around its adaxially glabrous leaves. It has both dioecious and gynoecious populations and cytotypes ranging from diploid to decaploid (R. J. Bayer and G. L. Stebbins 1987). It is probably a primary sexual progenitor of the A. parvifolia polyploid complex; the two taxa sometimes overlap morphologically; they differ in induments of basal leaves. Antennaria marginata may also be a contributor to the parentage of the A. howellii and A. rosea agamic complexes.

FNA 2006, Kearney and Peebles 1969

Duration: Perennial Nativity: Native Lifeform: Forb/Herb General: Dwarf perennial herbs, to 20 cm tall, tomentose, sometimes stipitate glandular, with wooly stolons; individuals staminate or pistillate, generally occurring equally in populations, however occasionally only pistillate individuals will be present. Leaves: Leaves mostly in a basal rosette, small, obovate to spatulate, 1-3 nerved, glabrous below with white wooly margins visible from the gray-tomentose abaxial faces, caulescent leaves reduced, linear. Flowers: Small discoid heads, staminate or pistillate, whitish, staminate corollas tubular, 5-toothed, pistillate corollas filiform, involucre strongly graduated, phyllaries thin, membranaceous, and papery, borne in corymbiform arrays in groups of 5-8. Fruits: Achenes small, the pappus of the pistillate flowers of copious capillary bristles, pappus of the staminate flowers of club-shaped, slightly flattened bristles. Ecology: Found on rocky slopes and ridges, in moist forests, ponderosa pine, Engelmann spruce, or Gamble oak communities, from 5,000-9,500 ft (1524-2896 m); flowering April-July. Distribution: Arizona, California, Colorado, New Mexico, Texas, and Utah; Mexico. Notes: Pussytoes! The keys to this species are the tomentose margins of the leaves (visible from the glabrous underside), the capitate or cymose heads, and the finely stipitate-glandular inflorescence. Ethnobotany: Specific uses of the species are unknown, however the genus was used as an infusion to treat coughs and colds. Etymology: Antennaria is from Latin antenna, because the flowers look like insect antennae, while marginata means margined with another color. Synonyms: Antennaria dioica var. marginata, Antennaria fendleri, Antennaria marginata var. glandulifera, Antennaria peramoena Editor: LCrumbacher 2011