Map 1436, Pl. 336 a, b

Stems 0.3–1.2 m long, densely pubescent with short (0.3–0.5 mm), softer hairs that are mostly minutely gland-tipped and also sparse straight, more or less spreading, longer, bristly hairs 1.0–1.5 mm long. Median 3–5 leaf pairs usually moderately to strongly perfoliate, these 1–6 cm wide at the base. Leaf blades 9–20 cm long, 4–9 cm wide, oblanceolate to obovate or elliptic, those of the largest leaves occasionally slightly fiddle-shaped, the nonperfoliate leaves tapered at the base, sometimes to an indistinct, broadly winged petiolar base, tapered to a sharply pointed tip, the margins with relatively dense, stiff, ascending hairs, the upper surface moderately pubescent with short, straight, appressed hairs, the undersurface moderately to densely pubescent with short, soft, spreading hairs mostly along the veins. Flowers 1 or more commonly 2 or 3(4) per leaf axil (2–6[8] per node). Paired bracts subtending each flower sometimes longer than the ovary but shorter than the flower (including the calyx and corolla), linear to narrowly lanceolate. Calyx lobes 10–18 mm long, the margins with dense, stiff, bristly, longer and shorter hairs, the inner and outer surfaces with scattered, short hairs, some of these often minutely gland-tipped. Corollas 8–17 mm long, dull red to purplish red, often mottled with small, cream-colored spots near the base and on the inner surface, occasionally entirely greenish yellow, narrowly funnelform, the mouth only slightly oblique, the outer surface with gland-tipped hairs. Styles usually slightly to moderately exserted (to 5 mm beyond the corolla lobes). Fruits 7–10 mm in diameter, orangish yellow to orange, sparsely hairy at maturity. May–July.

Scattered nearly throughout the state, most abundantly in the Ozark and Ozark Border Divisions (eastern U.S. west to Minnesota, Nebraska, and Texas; Canada). Bottomland forests, mesic upland forests, bases and ledges of bluffs, edges of glades, and banks of streams and rivers; also roadsides.

This is the most abundant and widespread member of the genus in Missouri. See the treatment of T. aurantiacum for a discussion of problems in discriminating that species from T. perfoliatum.