Aruncus dioicus var. dioicus
Leaf surfaces glabrous or slightly hairy. Styles 0.3–0.8 mm. Follicles somewhat plump, 1.5–2 mm. Seeds 1.5–2 mm. 2n = 18.
Phenology: Flowering early summer.
Habitat: Rich woods, stream banks, north-facing roadsides, seeps, ditches
Elevation: 10–1500 m
Ala., Ga., Ky., Md., Miss., N.C., Ohio, Pa., S.C., Tenn., Va., W.Va.
Variety dioicus is abundant in the southern Appalachians and into the Piedmont, where it typically occurs on mesic north-facing wooded slopes and road sides.
"thick" is not a number.