Perennials, 30-130 cm. Stems 1(-2), branched distally, strongly winged, glabrous or sparsely to moderately hairy proximally, glabrous or sparsely hairy distally. Leaves glabrous or sparsely to densely hairy; basal blades oblanceolate, weakly to strongly lobed; proximal and mid blades oblanceolate to lanceolate, usually entire, sometimes dentate; distal blades usually lanceolate, entire. Heads 2-25+ per plant, in paniculiform arrays. Peduncles 2-8 cm, sparsely to moderately hairy. Involucres globoid, 8-15 × 10-16 mm. Phyllaries (connate proximally) sparsely to moderately hairy. Ray florets 8-13, pistillate, fertile; corollas yellow, 10-15 × 4-10 mm. Disc florets 200-400+; corollas yellow proximally, yellow to yellow-brown distally, 2.5-3.5 mm, lobes 5. Cypselae 1.8-2.3 mm, moderately hairy; pappi of 5-6 entire, aristate scales 1.3-2 mm. Flowering Jul-Sep. Around ponds, lakes, and bogs, swampy meadows; of conservation concern; 300-500 m; Mo., Va. M. C. Simurda and J. S. Knox (2000) presented ITS sequence data that placed a population of Helenium virginicum from the Ozark highlands of southern Missouri in a monophyletic group with six populations of H. virginicum from the Shenandoah Valley of Virginia. R. L. Rimer and J. W. Summers (Missouri Department of Conservation, pers. comm.) located 42 H. virginicum populations in six counties in the Ozark highlands of Missouri. G. A. Yatskievych (Missouri Botanical Garden, pers. comm. to editors) has stated, '.. . the existence of this taxon in Missouri is no longer a matter of a single odd population, but probably rather another case of a taxon with two disjunct centers following dissection of a range during the Pleistocene glaciation.'
Helenium virginicum is in the Center for Plant Conservation´s National Collection of Endangered Plants.
Fibrous-rooted perennial 2-10 dm, ±puberulent or villous- puberulent at least on the stem, the lower part of the stem generally spreading-villous; lvs decurrent but smaller, fewer, and more erect than in no. 1 [Helenium autumnale L.], entire or subentire, the lowermost ones oblanceolate, commonly deciduous, the others oblong or lanceolate to lance-linear, sessile, generally not much reduced upwards, 3-12 נ0.5-2 cm; heads in well developed plants numerous in an open, corymbiform, leafy-bracteate infl, the disk subglobose or ovoid-globose, 6-15 mm wide, red-brown or purplish; rays ca 8 to ca 13, neutral, sometimes purplish at base, (0.5-)1-2 cm (rarely wanting); disk-fls predominantly 4-merous; pappus- scales 5(-8), ovate or lanceolate, shortly awn-tipped, ca (0.5-)1 mm overall; 2n=28. Moist ground and waste places; Mass. and N.H. to Fla., w. to Wis., Ill., Mo. and Tex., apparently only intr. northward. June-Oct. (H. nudiflorum; H. polyphyllum)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.