Herb; stems subquadrangular, pilose, the hairs brownish, up to 5 mm. long; leaf blades oblong-elliptic, 4 to 12 cm. long, 1.5 to 6 cm. wide, obtusish at apex, acute at base, rather thin, entire or undulate, both surfaces pilose, the hairs up to 2.5 mm. long, those of the upper surface scattered, ascending, those of the lower surface confined to costa and lateral veins and more or less appressed; the cystoliths minute but easily seen under a lens; petioles up to 8 mm. long, pilose; flowers borne in axillary bracted clusters 1.5 to 2 cm. long; bracts ellip- tic, 12 to 15 mm. long, 4 to 5 mm. wide, obtusish at apex, acute at base, long-pilose; bractlets linear, up to 7 mm. long and 0.75 mm. wide near base, 1-nerved, pilose; calyx 4.5 mm. long, glabrous or bearing several minute hairs near tip of segments, these narrowly triangular, about 3 mm. long, 0.75 mm. wide at base; corolla 3 to 3.5 cm. long, white, striped with lilac, minutely pubescent, hypocrateriform, the lower half slender, tubular, about 1.5 mm. in diameter, the upper half cam- panulate, about 1 cm. broad at mouth, the limb 1.5 to 2 cm, broad, the lobes ovate, crenate, rounded; stamens included; ovary and style pilo- sulous; capsule clavate, about 1 cm. long, and 5 mm. broad, the lower half slender and solid, glabrous or sparingly pilosulous toward tip, 4-seeded; seeds flat, suborbicular, reddish brown, about 3 mm. in diameter, the flat surfaces glabrous, the edges puberulous, mucilagi- nous-tomentose when moistened; retinacula 2.5 mm. long, fimbriate at apex. Type in the U. S. National Herbarium No. 1517990, collected in for- estat fibría, Comisaría of Putumayo, Colombia, 325 meters altitude, November 1930, by G. Klug (No. 1696). Ruellia putumayensis resembles no other Ruellia hitherto described. It can be recognized by its white lilac-striped corollas and the dense pilosity of the stems and the upper surface of the leaf blades.