Northern Prairie Wildlife Research Center
Aquatic and Wetland Vascular Plants of the Northern Great Plains
49. Asteraceae, the Aster Family
18. Vernonia Schreb. -- Ironweed
1. Vernonia fasciculata Michx.
Stout, erect perennial 4-12 dm tall, from a thick rootstock; stems single
or clumped, often reddish or purplish, glabrous below to puberulent above, especially
in branches of the inflorescence. Leaves simple, alternate, short-petioled,
lanceolate to ovate-lanceolate, 4-15 cm long, 0.8-4.5 cm wide, smooth to scabrous
above, dark-pitted beneath, acute to acuminate, denticulate to serrate, cuneate
at the base. Inflorescence corymbiform, the heads usually numerous and
crowded in flat-topped clusters; heads discoid; involucres campanulate,
6-9 mm high, the bracts imbricate, green with purple tips, obtuse to subacute,
finely villous on the margins; receptacle flat, naked; disk florets
all perfect, the corollas purple; style branches slender and tapered, puberulent.
Achenes 3-4 mm long, strongly ribbed; pappus of numerous purplish
to coppery capillary bristles. Mid Jul--Oct. Wet meadows, stream banks, ditches,
flood plains and prairie swales; frequent in the e and c parts, rare in the
w; (OH to Man. and Sask., s to MO and n TX).
Northern Great Plains plants are mostly subsp. corymbosa (Schwein. ex Keating)
S. B. Jones, which has middle cauline leaves less than 10 cm long and
scabrous above, and inner involucral bracts 2-3 mm wide. Entering our
range in se SD, c and e NE is subsp. fasciculata, with middle cauline
leaves 8-15 cm long, glabrous above or nearly so, and with inner involucral
bracts up to 2 mm wide.
Previous Section -- Sonchus arvensis L. -- Field
Return to Family -- Asteraceae - The
Next Section -- Xanthium strumarium L.