Fl. Amer. Sept. 2: 737. 1813. (as lyoni)
Stems 35–100 cm. Leaves: petiole (2–)10–40 mm; blade broadly lanceolate to ovate, 37–137 × (20–)30–55(–80) mm, base rounded to truncate, margins once-serrate, teeth 3–8 per cm, abaxial surface glabrous or pilose to slightly villous, adaxial glabrate or mostly glabrous. Cymes 27–71 mm; bracts 2–7 × 2–8 mm, ape× obtuse to acute, sometimes acuminate. Flowers: calyx lobes 5–11 × 3–7 mm, margins sparsely to densely ciliate; corolla pink-red to purple, tube 15–21 mm, abaxial lobes 10–12(–14) × 5–12 mm, adaxial strongly keeled; palate yellow-bearded; adaxial filaments 16–23 mm; staminode (8–)10–15 mm, ape× white to light pink; style 20–30 mm. 2n = 28.
Phenology: Flowering Jun–Oct.
Habitat: Stream banks, cove and spruce-fir forests, balds.
Elevation: 60–2000 m.
Ala., Ga., Miss., N.C., S.C., Tenn.
Garden escapes of Chelone lyonii are reported from Connecticut, Maine, Massachusetts, and New York. Chelone lyonii can be distinguished from other members of the genus by its longer petioles, rounded to truncate leaf bases, and white to light pink staminodes. It is sometimes confused with C. obliqua, especially where C. lyonii is found with leaves narrowed to the base. Chelone lyonii can be distinguished from C. obliqua by wider leaf blades, longer petioles, more strongly keeled corollas, shorter abaxial corolla lips, and longer staminodes. Chelone lyonii has been proposed as a diploid progenitor for the allopolyploid C. obliqua (A. D. Nelson 1995; Nelson and W. J. Elisens 1999).