Antennaria media

Dioecious or gynoecious (staminate plants rare or in equal frequency to pistillates, respectively). Plants 5–13 cm. Stolons 1–4 cm. Basal leaves 1-nerved, spatulate to oblanceolate, 6–19 × 2.5–6 mm, tips mucronate, faces gray-pubescent. Cauline leaves linear, 5–20 mm, not flagged (apices acute). Heads 2–5(–9) in corymbiform arrays. Involucres: staminate (3.5–)4.5–6.5 mm; pistillate 4–8 mm. Phyllaries distally dark brown, black, or olivaceous. Corollas: staminate 2.5–4.5 mm; pistillate 3–4.5 mm. Cypselae 0.6–1.6 mm, glabrous or papillate; pappi: staminate 2.5–4.5 mm; pistillate 4–5.5 mm. 2n = 56, 98, 112.

Phenology: Flowering summer.
Habitat: Dry, rocky to moist alpine tundra
Elevation: 1500–3800 m

Distribution

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Alta., B.C., N.W.T., Yukon, Alaska, Ariz., Calif., Colo., Idaho, Mont., Nev., N.Mex., Oreg., Utah, Wash., Wyo.

Discussion

Antennaria media ranges from Arizona to Alaska; dioecious and gynoecious populations are encountered (R. J. Bayer and G. L. Stebbins 1987). The dioecious (sexual) populations are restricted primarily to California and Oregon (Bayer et al. 1990). The main distinction between A. media and A. alpina is flags on distal cauline leaves present in A. alpina and mostly absent in A. media (Bayer 1990d). Phyllaries of the pistillate plants in A. alpina tend to be acute; they are blunter in A. media. At some point, it may be preferable to follow W. L. Jepson ([1923–1925]) and some later authors and treat A. media as a subspecies of A. alpina. Antennaria media appears to be an autopolyploid derivative of A. pulchella; genes from A. pulchella may have introgressed into the A. alpina and A. parvifolia complexes indirectly through A. media.

Selected References

None.

Lower Taxa

None.