Suffrutescent plants up to 1.3 meters (type 5 ft. high, Schultes and Cabrera); stems subquadrangular, glabrous below, the upper portions more or less densely and minutely puberulous the hairs appressed, up to 0.16 mm. long; leaf blades oblong-obovate to oblong, up to 32 cm. long and 13.5 cm. wide, more or less abruptly acuminate, the tip slender and sometimes curved, cuneate at base and decurrent on the petiole, rather thin, entire or undulate, the upper surface sparingly hirsute, the hairs 0.5 mm. long, subappressed, the lower surface minutely strigose on costa and veins, the hairs mostly closely ap- pressed, up to 0.16 mm. long, the venation moderately prominent (lateral veins 12 to 14 pairs); cystoliths blackish, up to 0.2 mm. long; petioles up to 7 cm. long, winged nearly to the base, the width of the wing expanse 1 to 2 cm. at base of leaf blade; glabrous or nearly so; flowers borne in narrow racemes (up to 20 cm. long and 3 cm. broad), several to a node or in pairs near tip of inflorescence, the rachis and peduncle (up to 2.5 cm. long) minutely and densely hirtellous, the hairs up to 0.2 mm. long, appressed to ascending; bracts lanceolate, up to 6 mm. long and 2 mm. wide at base, gradually narrowed to a slender tip, subcarinate, glabrous or nearly so, ciliolate; bractlets similar to the bracts in size and shape, glabrate; pedicels up to 5 mm. long, sparingly and minutely hirtellous to glabrous; calyx red, the segments lanceolate, 25 mm. long, 3 mm. wide near base, gradually narrowed to a slender tip, glabrous, delicately nerved, minutely ciliolate; corolla yellow (Schultes and Cabrera), up to 4 cm. long (probably longer when fully expanded), the tube narrowly campanu- late, 3 mm. broad at base, 6 mm. broad at throat, the lower part glabrous, puberulous above, the hairs more or less spreading and curved, up to 0.32 mm. long, the tip of the corolla rostrate, the upper lip lanceolate, 11 mm. long, 3.5 mm. wide at base, the lower lip ovate, conduplicate, 12 mm. wide at base, gradually narrowed to an obtuse tip, this 3-lobed, the lobes 1 mm. long, 0.5 mm. wide, rounded at tip; stamens 2, glabrous, exserted several mm. beyond mouth of corolla tube but slightly shorter than lips (perhaps more exserted in fully expanded flowers); anthers 5.5 mm. long, 1.5 mm. broad, rounded at both ends, the connective extended at tip, forming a small mucro, one of the anthers 2-lobed, the extra lobe about 4 mm. long; style reaching tip of corolla lips, the stigma oval, obtuse, about 0.75 mm. long and 0.5 mm. wide; capsule glabrous, about 2 cm. long, 4-seeded, the seed-bearing portion 11 mm. long, 4 mm. broad and 3 mm. thick; retinacula 2.5 mm. long, the tip lacerate and rounded; seed brown, flattened, ovate, 4 mm. long, 3 mm. broad, 0.5 mm. thick, the tip bearing an undulate rounded crest, 0.5 mm. long at middle, the sur- face of the seed muricate.
Type in the U. S. National Herbarium, No. 2124645, collected at Mocoa, Comisaría of Putumayo, Colombia, "1,800-2,400 feet" altitude, March 16, 1953, by Richard Evans Schultes and Isidoro Cabrera (No. 19093). Schultes and Cabrera's No. 19095, collected nearby on the same day, is also of this species.
Kalbreyeriella cabrerae is a well-marked species differing from the other two Colombian species in its large oblong to oblong-obovate leaves and the yellow flowers.