Purplehead Sneezeweed

It has been suggested that Helenium flexuosum may be of hybrid origin from H. campestre (perennial, 2n = 28) and some member of Helenium sect. Tetrodus (H. F. L. Rock 1957). The only member of sect. Tetrodus that has a chromosome number of 2n = 28 is H. linifolium, an annual from southern Texas.

Perennials, 30–100 cm. Stems usually 1, usually branched distally, strongly winged, glabrous or sparsely hairy proximally, sparsely to moderately hairy distally. Leaves glabrous or sparsely to moderately hairy; basal blades oblanceolate to obovate or spatulate, entire or serrate; proximal and mid blades oblanceolate to lanceolate, entire or toothed; distal blades lanceolate to lance-linear, entire. Heads (1–)5–50(–80+) per plant, in paniculiform arrays. Peduncles 3–10 cm, sparsely to moderately hairy. Involucres globoid to usually ovoid, 8–17 × 9–17 mm. Phyllaries (connate proximally) moderately to densely hairy. Ray florets usually 8–13, neuter, sometimes 0; corollas yellow to reddish brown to red to purple, 10–20 × 5–10 mm. Disc florets 250–500(–700+); corollas yellow proximally and purple distally or purple throughout, 2.3–3.7 mm, lobes 4(–5). Cypselae 1–1.2 mm, moderately hairy; pappi of 5–6 entire, aristate scales 0.6–1(–1.7) mm. 2n = 28.

Helenium nudiflorum Nuttall

Helenium nudiflorum Nutt. Trans. Am. Phil. Soc. II. 7: 384
1841.
Helenium quadridenlatum Hook. Comp. Bot. Mag. 1: 98. 1835. Not H. quadridenlatum Labil!.
1792. ? Helenium flexuosum Raf. New Fl. 4: 81. 1838. ? Helenium dicholomum Raf. New Fl. 4: 81. 1838. Helenium micranlhum Nutt. Trans. Am. Phil. Soc. II. 7: 385. 1841. Leptopoda brachypoda T. & G. Fl. N. Am. 2: 388. 1842. Helenium purpureum Hale; T. & G. Fl. N. Am. 2: 388, as synonym. 1842. Heleniu-m atropurpureum Kunth & Bouche, Ind. Sem. Berol. 1845: 21. 1845. ? Helenium atropurpureum grandicephalum Lemaire, 111. Hort. pi. 375. 1863. Helenium Brachypoda Wood, Bot. & Fl. 182. 1870. Helenium seminariense Featherman, La. Univ. Rep. 1870: 74. 1871. Heleniastrum nudiflorum Kuntze, Rev. Gen. 342. 1891.
A tall perennial; stem 2-10 dm. high, simple below, narrowly winged, puberulent; basal
leaves oblanceolate or spatulate, 5-10 cm. long, thin, short-pctioled, more or less hirsute,
entire or repand; upper stem-leaves scattered, linear-lanceolate, 3-5 cm. long, puberulent; heads corymbose, radiate or discoid; bracts linear-subulate, 5-7 mm. Long; ray-flowers neutral; ligulcs 1-1.5 cm. long, with a narrow base, yellow or partly or wholly brown-purple (II. purpureum and //. atropurpureum) or wanting; disk ovoid-globose, brownish-purple, 6-10 mm. broad; corollas 2-2.5 mm. long, glandular-granuliferous; tube minute; achenes about 1 mm. long; squamellac ovate or lanceolate, acute to awn-tipped, 0.5 mm. long.
TypB locality: Plains of Red River, Arkansas.
Distribution: Rhode Island; Pennsylvania to Illinois, Arkansas; Texas, and Florida.

Helenium flexuosum is a North American plant species in the daisy family known by the common name purple sneezeweed. It is widespread across much of eastern and central United States and Canada, from Nova Scotia west to Ontario, Minnesota, and Kansas, south to Florida, Louisiana, and eastern Texas.

Helenium flexuosum is a perennial herb up to 100 cm (40 inches) tall. One plant can produce 80 or more flower heads in a branching array. Each head has up to 700 yellow or purple disc florets, sometimes with no ray florets, sometimes with 8-13 yellow, red, purple, or brown ray florets. The species grows in fields, ditches, and streambanks.