Herb, sometimes suffrutescent at base; stems up to 1 meter high, subquadrangular, glabrous or thinly pubescent with minute white curved hairs, these sometimes in lines; leaf blades ovate-lanceolate, up to 16 cm. long and 6 cm. wide, acuminate at apex, acute and decur- rent on petiole at base, undulate, bright green, glabrous except the costa and lateral veins (6 to 8 pairs), these pubescent with small appressed hairs, the cystoliths numerous, conspicuous under a lens; petioles up to 4 cm. long, glabrous or minutely pubescent; flowers borne in small, opposite, sessile clusters, forming a terminal naked spike or contracted thyrse, the lowermost clusters in the axils of the upper leaves, the uppermost clusters confluent; rachis pubescent, the hairs minute, curved; bracts linear, 1 to 2 cm. long, 0.5 to 1 mm. wide, or occasionally larger and more leaflike; bractlets triangular-subulate, 1 to 5 mm. long, minutely pubescent; calyx 4 to 6 mm. long, the seg- ments linear-subulate, 3 to 4 mm. long, about 0.5 mm. wide at base, dark colored in dried specimens, bearing a few minute hairs, the cystoliths prominent under a lens; corolla 3 to 3.5 cm. long, white, blue, violet, red, or pink with dark stripes, glabrous above, the lower half of the tube slender, pilosulous, about 1.5 mm. in diameter, the upper half campanulate, slightly oblique, 8 to 9 mm. at mouth, the limb about 1.5 cm. broad, the lobes ovate, about 10 mm. long and 7 mm. wide, emarginate, somewhat irregular; stamens included; capsules 12 mm. long, glabrous, the solid stipitate portion about 8 mm. long, the seed-bearing portion flattened, oval, about 3 mm. broad, 4-seeded; retinacula 1.5 mm. long; seed suborbicular, flat, reddish brown, 3.25 mm. broad, the flat surfaces glabrous, the margins minutely muci- laginous-tomentose when moistened. Type in the U. S. National Herbarium, No. 1043209, collected in quebrada in forest, Tierra Alba on the Río Sinú, Department of Bolívar, Colombia, 70 to 150 meters altitude, by Francis W. Pennel (No. 4658). Isotypes are in the Gray Herbarium and the herbarium of the New York Botanical Garden. The species is also represented by the following collections: ANTIOQUIA: Banks of the Río Cauca at Puerto Valdivia, 240 to 260 meters altitude, Metcalf & Cuatrecasas 30075 (Mo, US).

CALDAS: Moist soil at Manizales, near the Río Chinchina, 1,300 to 1,400 meters altitude, Pennell 10184 (GH, NY). CAUCA: Primeval forest at El Tambo, 700 meters altitude, von Sneidern 971 (8); 1012 (8). CHOCO: Dense forest along the Quebrada Jellita, Bahía Solano, 50 to 100 meters, Killip & Garcia 33559 (US). EL VALLE: Forest along the Río Sabaletas, Km. 29 of highway from Buena- ventura to Cali, vicinity of Sabaletas, 25 meters altitude, Killip & Cuatrecasas 38857 (US).

SANTANDER: Magdalena Valley, in the vicinity of Barranca Bermeja between Sogamoso and Carare Rivers, 100 to 500 meters, Haught 2099 (US). Magdalena Valley, in the vicinity of Barranca Bermeja, between the Sogamosa and Colorado Rivers, 100 to 500 meters, Haught 1498 (US); 1561 (US); 1580 (US). Ruellia pennellii is, apparently, distinct from all other Colombian species hitherto described, being related to the following new species, R. colombiana. The variation in the color of the corolla is indeed remarkable.