Packera antennariifolia (Britton) W. A. Weber & Á. Löve (redirected from: Senecio antennariifolius)
Family: Asteraceae
[Senecio antennariifolius Britton]
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Perennials, 20-40+ cm; rhizomatous (rhizomes branched, horizontal to suberect). Stems 1 (sometimes from rosettes, rosettes sometimes clustered), tomentose. Basal leaves petiolate; blades broadly lanceolate to elliptic or spatulate, 20-40+ × 10-20+ mm, bases tapering, margins entire or subentire to dentate distally (faces tomentose). Cauline leaves abruptly reduced (petiolate or sessile; narrowly lanceolate to sublyrate, sharply toothed to pinnatisect or entire). Heads 6-12+ in corymbiform arrays (lateral cymiform arrays sometimes originating in leaf axils). Peduncles bracteate, densely lanate to sparsely tomentose. Calyculi inconspicuous. Phyllaries 13 or 21, green, 5-7 mm, densely tomentose (apices scarious). Ray florets 8-10(-13); corolla laminae 5-10 mm. Disc florets 25-35+; corolla tubes 3-4 mm, limbs 1.5-2 mm. Cypselae 1-1.5 mm, hirtellous on ribs; pappi 4-5 mm. 2n = 46.

Flowering late Apr-late May. Slopes on shale barrens; 300-800 m; Md., Pa., Va., W.Va.

Packera antennariifolia is known only from shale barrens or shale-derived soils in central Appalachia. Plants growing on steep slopes have stouter, more horizontal caudices and more extensive fibrous roots than specimens from other locations. Specimens from shale-derived soils, not growing directly on shale barrens, have weakly lobulate leaves and noticeably less hairiness.

Much like no. 4 [Senecio canus Hook], even more closely tomentose, but the upper lf-surfaces commonly soon glabrate; basal lf-blades mostly elliptic or obovate, 1-4 cm נ6-20 mm, shallowly and rather remotely dentate to occasionally entire; cauline lvs few and much reduced, linear and entire or pinnatifid with linear segments; achenes hirtellous on the angles; 2n=46. Shale-barrens; s. Pa. to Va. and W.Va. Apr.-June.

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

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