Arnica acaulis

Plants 20-80 cm. Stems simple. Leaves 2-4(-6) pairs, nearly all basal; sessile; blades (with 3, 5, or 7 prominent, subparallel veins) broadly elliptic, ovate, or rhombic, 4-15 × 1.5-8 cm, margins mostly entire, apices mostly obtuse, faces hirsute and stipitate-glandular (cauline leaves 0 or 1-2, distalmost often alternate, much reduced). Heads 3-20. Involucres campanulate. Phyllaries 12-18, narrowly ovate. Ray florets 10-16; corollas yellow. Disc florets: corollas yellow; anthers yellow. Cypselae dark gray to dark brown, 5-7 mm, glabrous or sparsely stipitate-glandular; pappi white, bristles barbellate. 2n = 38.

Flowering Apr-Jun. Sandy pine woods and clearings, often in damp soils, chiefly on Coastal Plain; 0-300 m; Del., D.C., Fla., Ga., Md., N.J., N.C., Pa., S.C., Va.

Perennial 2-8 dm from a short, simple, erect caudex 5-20 mm, with numerous fibrous roots; herbage glandular and hirsute; basal lvs rosulate, sessile or nearly so, broadly elliptic to ovate or even rhombic, obscurely toothed or subentire, 4-15 נ1.5-8 cm; cauline lvs few and reduced, the uppermost often alternate; heads 3-20, campanulate, the disk 13-20 mm wide; invol 10-12 mm; rays 10-15, 1.5-2.5 cm; pappus white, merely barbellate; 2n=38. Sandy pine woods; Del. and se. Pa., s. mainly along the coastal plain to Fla. May-July.

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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