Suffrutescent herbs or shrubs up to 1 meter high or more; stems sub- terete, glabrous below, pubescent at tip, the hairs curved, ascending, about 0.25 mm. long; leaf blades lanceolate, up to 18 cm. long and 4 cm. wide, slenderly acuminate, narrowed gradually from about the middle to base, there abruptly narrowed and subauriculate, drying dark olive-green, firm, entire or undulate, the upper surface glabrous, the costa impressed, the venation obscure, the lower surface sparingly puberulous, the hairs confined chiefly to the costa and lateral veins (8 to 10 pairs), these rather prominent, the cystoliths minute and in- conspicuous even under a lens; petioles up to 1 cm. long, puberulous; flowers solitary or several borne in fascicles in narrow spikelike termi- nal simple or forked racemes up to 18 cm. long, the peduncle up to 6.5 cm. long, this and the rachis pubescent, the hairs brownish, curved, ascending, about 0.25 cm. long, the lowermost internode of the rachis about 2 cm. long, the others successively shorter toward the tip of the raceme, the lowermost pair of bracts leaflike, narrowly lanceolate, up to 1.5 cm. long, the others subulate, 2 mm. long and about 0.5 mm. wide at base, ciliate, reduced in size toward tip of raceme; bractlets similar but slightly smaller than the bracts; calyx 3 to 3.5 mm. long, puberulous, the segments narrowly lanceolate, slightly more than 0.5 mm. wide at base, acuminate at tip; pedicels slender, about 2 mm. long, puberulous; corolla (immature) about 8 mm. long, white (?), pubescent, the hairs more or less spreading, about 0.3 mm. long; capsules not seen. Type in the U. S. National Herbarium, No. 1852697, collected in woods at La Elsa, on the right bank of Río Digua, Department of El Valle, Colombia, 1,000 to 1,200 meters altitude, November 9, 1913, by J. Cuatrecasas (No. 15317). An isotype is in the herbarium of the Chicago Natural History Museum. Such characters as its slender, simple or forked racemes and its lanceolate, slenderly acuminate, chartaceous leaf blades serve to iden- tify Pseuderanthemum hylophilum. Only immature corollas are pres- ent on the type material; the color of these is not apparent. The specific epithet is derived from λn, forest, and piλew, to love.