2. Helenium autumnale L. (common sneezeweed, autumn sneezeweed)
H. autumnale var. canaliculatum (Lam.) Torr.
& A. Gray
H. autumnale var. parviflorum (Nutt.) Fernald
Pl. 279 e, f;
Map 1185
Plants perennial
herbs, with fibrous roots. Stems erect or ascending, 30–150 cm long, few- to
many-branched above the midpoint, narrowly several-winged, glabrous or sparsely
to densely pubescent with short, sometimes curved or curled, more or less
spreading to loosely ascending hairs, also moderately dotted with sessile to
impressed, yellow glands. Leaves glabrous or more commonly moderately to
densely pubescent with short, sometimes curved, mostly spreading hairs, also
densely dotted with sessile to impressed, yellow glands. Basal and lowermost
stem leaves absent or withered at flowering, somewhat smaller than the median
stem leaves, the blade oblanceolate to obovate, unlobed or with a few shallow,
rounded, pinnate lobes. Median and upper stem leaves 4–15 cm long, oblanceolate
to elliptic, less commonly lanceolate, oblong, or obovate, unlobed, the margins
entire or finely to coarsely toothed (often only above the midpoint), tapered
at the base, long-decurrent as narrow wings of green tissue along the stem,
angled or tapered to a usually sharply pointed tip. Involucre 8–20 mm long,
8–23 mm in diameter, the outer series of involucral bracts fused at the base,
the midnerve inconspicuous, not thickened, the outer surface moderately to densely
pubescent with minute, curved hairs, both surfaces also moderately
gland-dotted. Ray florets 8–21, pistillate (with a 2-branched style exserted
from the short tube at flowering and a well-developed ovary that potentially
develops into a fruit), the corolla (3–)8–25 mm long, yellow. Disc florets with
the corolla 2.5–3.5 mm long, yellow, 5-lobed. Pappus of mostly 5–7 scales,
0.5–0.9 mm long, the awned tip relatively short. Fruits 1–2 mm long, narrowly
wedge-shaped, with (5–)8 often lighter-colored ribs, the surface brown,
moderately to densely pubescent with white to straw-colored hairs, mostly along
the ribs. 2n=32, 34, 36. August–November.
Scattered nearly
throughout the state, but uncommon or absent in the Mississippi Lowlands
Division and the western portion of the Glaciated Plains (nearly throughout the
U.S.; Canada). Banks of streams, rivers, and spring branches, margins of ponds,
lakes, and sinkhole ponds, sloughs, fens, and calcareous seeps, marshes,
bottomland prairies, moist depressions of upland prairies, and bottomland
forests; also pastures, ditches, railroads, roadsides, and moist, open,
disturbed areas.
This widespread
species comprises populations exhibiting complex variation for an array of
morphological characters that seem to vary independently, and several
infraspecific taxa have been described. Steyermark (1963) accepted three
varieties as occurring in Missouri: the smaller-headed var. parviflorum,
the narrow-leaved var. canaliculatum, and the var. autumnale for
plants not fitting either of the preceding extremes. There seems little purpose
served in attempting to recognize formal infraspecific taxa in Missouri.
For a discussion
of putative hybrids between this species and other perennial sneezeweeds, see
the treatments of H. flexuosum and H. virginicum. Native
Americans used a powder from the dried heads of this and other species of Helenium
as snuff to induce sneezing as a treatment for headaches, colds, blocked
sinuses, and so on (Moerman, 1998). An infusion of the stems was applied to the
skin for fevers.