Verbesina virginica L.
CC = 5
CW = 3
MOC = 47
Family - Asteraceae/Heliantheae
Habit - Perennial forb with often somewhat fleshy roots.
Stems - Erect, To 2 m, winged (the wings to 3 mm broad), often only below the midpoint, typically simple, single or multiple from base, densely pubescent with short, curved, often somewhat felty or woolly hairs, especially toward the tip.
Leaves - Alternate, simple, mostly petiolate. Petioles short, poorly differentiated, winged, the base minutely to strongly decurrent below the attachment point as a pair of wings. Blades 5-20 cm long, narrowly elliptic or lanceolate-elliptic to ovate, tapered at the base, tapered to a sharply pointed tip, the margins coarsely to finely toothed to nearly entire, the upper surface sparsely to moderately roughened-pubescent with short, fine, broad-based hairs, the undersurface moderately to densely pubescent with short, fine, sometimes felty hairs.
Inflorescences - Usually terminal panicles with 40-200 heads, rarely reduced to an open cluster. Peduncles pubescent to subtomentose.
Heads - Involucre 3-7 mm in diameter, more or less conical, with 8-13 bracts. Involucral bracts 2.5-5.5 mm long, oblong-oblanceolate to oblanceolate, appressed or ascending at flowering, the outer surface densely hairy. Chaffy bracts narrowly oblong to narrowly oblong-oblanceolate, densely hairy toward the tip.
Florets - Ray florets pistillate, 1-5 per flower head, the corolla 3-9 mm long, spreading to somewhat drooping, notched at apex, broadly oblong, white. Disc florets 8-12 per head, perfect, the corolla 2.5-3.5 mm long, white, the lobes acute. Pappus of the ray and disc florets similar, of 2 slender awns 1.5-3.0 mm long, with fine, upward-pointed barbs, more or less persistent at fruiting. Stamens 5, slightly exserted. Anthers purplish-black, to 2 mm, connate around style. Style whitish, bifurcate, exserted.
Fruits - Achenes ascending to somewhat spreading at maturity (forming a more or less hemispherical mass), 3.5-6.0 mm long, the body usually oblanceolate, compressed, usually relatively broadly winged, less commonly narrowly winged or wingless, the surface sparsely to moderately pubescent with fine, pustular-based hairs. Pappus of two short awns.
Flowering - August - October.
Habitat - Streambanks, bases of bluffs, forests, pastures, railroads, and roadsides.
Origin - Native to the U.S.
Lookalikes - None when flowering. Vegetatively similar to other members of the genus.
Other info. - This plant is found in Missouri only in the southern half of the state, where it is common. Beyond Missouri its range extends throughout most of the southeastern quadrant of the continental U.S. It is easily recognized by its conspicuously winged stems and white flowers (both rays and disks are white). There are yellow flowered species of this genus in Missouri but this is the only white flowered species. Under optimal conditions it can form dense stands. It is a flagship species for formation of frost flowers on the first hard freezes of late autumn. These occur when fine, longitudinal splits in the lower stem exude plant sap, which then freezes, forming ribbons of ice. These interesting formations are very ephemeral, typically lasting only a few hours.
Photographs taken in the Ozark Scenic Riverways, Shannon County, MO., 8-20-03 (DETenaglia); also at Shaw Nature Reserve, Franklin County, MO, 8-15-2006, Ha Ha Tonka State Park, Camden County, MO, 9-2-2012, and Onondaga Cave State Park, Crawford County, MO, 8-20-2014 (SRTurner). Frost flower image from Meramec State Park, Franklin County, MO, 11-21-2016 (SRTurner).