Shrubby, thorny plants up to 2 meters high; stems subtomentose toward tips, glabrate below; leaf blades oblong-elliptic, 6 to 7 cm. long, 2 to 3 cm. wide (the spines not included), coriaceous, glabrous or the costa and veins (10 or 12 pairs) bearing a few weak hairs, the margins serrate-dentate, the teeth triangular, 2 to 5 mm. high, ending in sharp spreading spines up to 5 mm. long, the upper surface bright green, drying light olive-green, the lower surface drying dark olive- green, the venation very prominent, especially on the lower surface, the veinlets coarsely reticulate toward margins; petioles up to 5 mm. long, rather sparingly pilose; interpetiolar bracts ovate or suborbicu- lar, 3 to 5 mm. long and wide, serrate-dentate, the teeth terminating in spines, the terminal one as much as 7 mm. long; flowers borne in ter- minal and subterminal spikes 5 to 7 cm, long and about 2 cm. broad (the corollas excluded), the peduncles (about 8 mm. long) and rachis brown-puberulous; bracts lanceolate, about 20 mm. long including the terminal spine (2.5 mm. long), 4 mm, wide, acute, coriaceous, sparing- ly ciliate, otherwise glabrous, the costa prominent; bractlets narrowly lanceolate, 12 mm. long, including the terminal spine (2.5 to 2 mm. long), 2 mm. wide, acuminate, subcarinate, coriaceous, the costa promi- nent, terminating in a spine about 3 mm. long; calyx 1 cm. long, the segments subequal, chartaceous, lanceolate, 2.5 to 4 mm. wide, abruptly acute and at least some of them minutely dentate near tip (2 to 4 teeth), all terminating in a spine about 1 mm. long, glabrous or bearing a few minute hairs and sparingly ciliolate; corollas 4.5 cm. long, yellow distally, orange proximally (Cuatrecasas), finely pubescent, the hairs segmented, up to 0.5 mm. long or a few of them slightly longer, the tube slightly curved, 3 mm, broad at base, narrowed at about 5 mm. above base to 2.5 mm., thence rather abruptly enlarged to 5.5 mm., the throat 6 mm. broad, the portion from about 1.5 cm. above base to mouth tubular, the upper lip obovate, erect, 1 cm. long, 3 mm. wide at base, 4 mm. wide near tip, emarginate, the lobes triangular, obtuse, sometimes bilobed at tip, the lower lip 3-lobed, more or less spreading, the lobes oval, 5 mm. long, 2.5 mm. wide, obtuse or rounded, the sinuses rounded; stamens and pistil terminating at tip of upper corolla lip, the filaments glabrous except at juncture with connective, here dorsally pilose, the hairs up to 1 mm. long; anthers 5 mm, long, pilose at tip; style glabrous; ovary glabrous; mature capsule not seen.
Type in the U. S. National Herbarium, No. 1900471, collected at Cuchilla de Barragán, valley of Río Bugalagrande, Department of El Valle, Colombia, 3,300 to 3,320 meters altitude, March 20, 1946, by J. Cuatrecasas (No. 20236).  Distantly related to Aphelandra cirsioides Lindau, of Ecuador and Peru, A. euopla can be separated readily from this by its relatively broader leaf blades and larger (20 cm. long) entire bracts. The leaf blades of A. cirsioides are rarely over 2 cm. wide and the bracts are only 15 mm. long and spiny-margined. The name euopla (etorλos) means well-armed, in allusion to the spiny character of the plant.