4. Cirsium carolinianum (Walter) Fernald & B.G. Schub. (Carolina thistle, small-headed thistle)

Pl. 253 f, g; Map 1053

Plants biennial or short-lived perennials, with a short, inconspicuous taproot in addition to the often somewhat thickened, fibrous roots. Stems 50–150 cm long, unbranched or more commonly few-branched toward the tip, glabrous or with patches of cobwebby hairs (especially when young), without spiny-margined wings. Basal leaves 8–30 cm long, 1–3 cm wide (to 5 cm wide if lobed), narrowly lanceolate to narrowly oblanceolate or linear, tapered at the base, mostly sharply pointed at the tip, unlobed or less commonly with a few narrow, irregular lobes below the midpoint, the margins otherwise toothed or wavy and spiny, the upper surface appearing green, nearly glabrous to moderately pubescent with stiff, straight hairs, the undersurface appearing white, densely pubescent with felty hairs. Stem leaves progressively reduced from the stem base, those along the upper 1/3 few, and widely spaced, mostly 1–15 cm long, all unlobed or the lower ones with a few narrow, irregular lobes below the midpoint, tapered to an often slightly expanded, nondecurrent base, otherwise like the basal leaves. Heads usually relatively few, solitary at the branch tips, appearing long-stalked. Involucre 15–20 mm long, as long as or slightly longer than wide (often appearing broader when pressed), often somewhat cobwebby-hairy, the lower and median bracts tapered to a loosely ascending to spreading, spiny tip, this 1.5–4.0 mm long, straw-colored to light yellow. Corollas 15–24 mm long, pinkish purple to reddish purple, the lobes 4–7 mm long. Pappus 12–17 mm long, white or occasionally slightly grayish-tinged. Fruits 3–4 mm long. 2n=20. May–June.

Scattered to uncommon in the eastern portion of the Ozark and Ozark Border Divisions, with a single historical specimen from Cooper County (southeastern U.S. west to Missouri and Texas). Openings of mesic to dry upland forests, rarely banks of streams and bottomland forests; also roadsides; usually on acidic substrates.