This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol3", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Erect, mostly branching herbs, with alternate, mainly decurrent, punctate bitter entire or dentate leaves, and large peduncled heads of both tubular and radiate, yellow or brownish-yellow flowers, or rays sometimes wanting. Involucre broad and short, its bracts in 1 or 2 series, linear or subulate, reflexed or spreading. Receptacle convex, subglobose or oblong, naked. Ray-flowers pistillate and fertile, or neutral, the rays cuneate, 3-5-lobed. Disk-flowers perfect, fertile, their corollas 4-5-toothed, the teeth glandular-pubescent. Anthers 2-toothed or sagittate at the base. Style-branches of the disk-flowers dilated and truncate at the apex. Achenes turbinate, ribbed. Pappus of 5-8 entire, dentate or incised, acuminate or aristate scales. [The Greek name of some plant, from Helenus or Helena.]
About 24 species, natives of North and Central America. In addition to the following, some 18 others occur in the southern and southwestern United States. Type species: Helenium autumnale L.
Leaves oblong-lanceolate or ovate-lanceolate, dentate; rays fertile; disk yellow.
1. H. autumnale.
Leaves lanceolate or linear-lanceolate, mainly entire; rays neutral; disk purple.
2. H. nudiflorum.
Leaves all linear-filiform, entire; rays fertile.
3. H. tenuifolium.
Perennial; stem puberulent or glabrous, rather stout, narrowly winged by the decurrent bases of the leaves, corymbosely branched above, 2°-6° high. Leaves firm, oblong, lanceolate or ovate-lanceolate, acuminate or acute at apex, narrowed to the sessile base, pinnately few-veined, 2'-5' long, 1/4' - 2' wide, dentate, denticulate or entire, puberulent, glabrous or pubescent, bright green; heads numerous, 1'- 2' broad, borne on long puberulent peduncles; bracts of the flattish involucre densely canescent; rays 10-18, drooping, bright yellow, equalling or longer than the globose yellow disk, pistillate and fertile, 3-cleft; achenes pubescent on the angles; pappus scales ovate.
In swamps and wet meadows, Quebec to Florida, Manitoba, Oregon, Nevada and Arizona. Yellow-star. Ox-eye. Sneezeweed. Ascends to 2600 ft. in Virginia. Aug.-Oct.
Helenium nudiflorum Nutt. Trans. Am. Phil. Soc.
(II) 7: 384. 1841. Leptopoda brachypoda T. & G. Fl. N. A. 2: 388.
Perennial; stem mostly slender, puberulent at least above, corymbosely branched near the summit, 1°-3° high, narrowly winged by the decurrent leaf-bases. Stem leaves lanceolate or linear-lanceolate, entire or sparingly denticulate, acute or obtusish at the apex, 1 1/2' - 3' long, 2"- 6" wide, sessile; basal and lower leaves spatulate, obtuse, more or less dentate, tapering into margined petioles; heads several or numerous, 1' - 1 1/2' broad, on slender or short-puberulent peduncles; rays 10-15 (sometimes wanting), drooping, yellow, yellow with a brown base, or brown throughout, 3-toothed, neutral, or with rudimentary pistils, sterile, equalling or exceeding the brown or purple globose disk; pappus scales ovate, aristate.
In moist soil, Missouri and Illinois to Texas, east to North Carolina and Florida. Also locally naturalized from Pennsylvania to Connecticut. June-Oct.
Annual; glabrous or minutely pubescent above; stem slender, very leafy and usually much branched, 8'-24' high. Leaves all linear-filiform, entire, sessile, often fascicled, 1/2' - 1 1/2' long, 1/2" or less wide; heads several or numerous, corymbose, 9" - 15" broad, borne on slender or filiform peduncles; bracts of the involucre few, linear or subulate, sometimes pubescent, soon reflexed; rays 4-8, fertile, 3-4-toothed, at length drooping, longer than the globose disk; achenes villous; pappus scales ovate, tipped with slender awns.
In moist soil, southeastern Virginia to Florida. Missouri, Kansas and Texas. Naturalized in waste places, northward to Massachusetts, and in Cuba and Santo Domingo. Aug.-Oct.