Costus whiskeycola sp. nov. (Fig. 20) looks quite similar to Costus erythrophyllus Loes., sharing many features of inflorescence and flowers, but it is markedly different in their leaves which lack the distinct plication and which have a dark, olive green adaxial surface.
Herb 0.5–0.7 m tall. Leaves sheaths 10–18 mm diam; ligule 10–20 mm long, obliquely truncate; petiole 5–15 mm long; sheaths, ligule and petiole glabrous, purple-red to green; lamina ovate-elliptic to narrowly ovate-elliptic, 22–29 × 10–13 cm, dark, olive green adaxially, red-purple to dark purple abaxially, with 5–6 dark green bands corresponding with slightly raised veins above, adaxial and abaxial surfaces both glabrous, base acute, apex acute to shortly acuminate (acumen 3–5 mm long). Inflorescence ovoid, ca. 7 × 4.5 cm, terminating a leafy shoot; bracts and appendages of bracts, bracteole, calyx, and ovary glabrous. Flowers abaxially oriented; bracts red, coriaceous, broadly ovate, 3–4 × 2–3.5 cm; appendages green, foliaceous, ascending, triangular-ovate, 2.5–5 × 2–3.5 cm, apex acute; bracteole boat-shaped, 24–30 mm long; calyx red, 12–20 mm long, lobes very shallowly triangular, 2–5 mm long; corolla white, 60–75 mm long, glabrous, lobes narrowly elliptic, 45–60 mm long; labellum white, distal edge horizontally spreading, broadly obovate, 60–70 × 50 mm, lateral lobes striped with red, middle lobe reflexed with yellow honey mark, irregularly lobulate, margin crenulate; stamen white, tinged with red, 35–40 × 13–14 mm, not exceeding the labellum, apex 3-dentate, anther 8–10 mm long. Capsule not seen. Distribution. Colombia (Putumayo). Ecuador (Napo), Peru (Loreto) (Fig. 22I).