Hemiepiphytic or terrestrial, trailing over the ground; stems appressed-climbing or scandent; internodes semi-glossy, 1.5–13.5 cm x 4–8 mm, longer than broad, medium or dark green to purplish brown, drying golden to red or rusty brown with wrinkled, sometimes flaky epidermis; roots usually 2 per node, sometimes highly branching, red-brown; cataphylls 15–18.5 cm, unribbed or bluntly 2-ribbed, D-shaped in cross section with bluntly rounded apex, light green to yellowish green, often tinged red, drying pale reddish tan and wrinkled, deciduous. LEAVES erect; petioles 6–11 cm x 3–5 mm (dry), D-shaped to broadly sulcate, medium green, tinged red, semiglossy, drying yellow-green, somewhat red with loose, wrinkled epidermis; blades ovate, thick and coriaceous, obtusely acuminate at the apex, obtuse at base, 12–21 x 5–12 cm, 1.6–2.3(–2.6)x longer than wide, (1.3–)2–2.5(–3.2)x longer than petiole; adaxial surface glossy, dark green, drying glossy, green or olive-green, abaxial surface paler, drying glossy and paler than adaxially; midrib flat and pale yellow-white adaxially, round-raised, paler than blade and tinged red abaxially; primary lateral veins etched adaxially, darker abaxially, 13 to 18 per side and very close together (ca. 1 cm apart), departing midrib at 30º–40º angles, drying concolorous and raised on both sides; cross veins numerous, minute, perpendicular, weakly etched adaxially, scarcely visible abaxially, drying concolorous and wrinkled on both sides. INFLORESCENCES erect, 1 per axil; peduncle 3–5 cm x 3– 8 mm (dry), much shorter than petiole, green, drying reddish olive; spathe semiglossy, thin and longtapered, 10.4–18 cm, drying red-brown; spathe blade pale green outside and inside; spathe tube medium green sometimes tinged rose outside, red-violet inside, with reddish orange resin canals inside tube; spadix long-tapered, white, 8–15.5 cm; pistillate portion 1.6– 2.1 cm long on back, 2.3–6.5 cm long on front, 8– 18 mm diam. (dry); staminate portion 5.7–9.7 cm x 6–10 mm from base to ca. 1 cm from apex where it begins to gradually taper (dry), narrower than pistillate portion, wider than sterile staminate portion; sterile staminate portion 0.5–1 cm x 5–7 mm throughout (dry), narrower than pistillate or fertile staminate portions; pistils ca. 8 x 7–10 mm, ovary 6- to 9-locular, ovules with subbasal placentation, 2 to 3 per locule. INFRUCTESCENCES with pistillate spadix 8–9 cm, berries globular, yellow-orange with red-brown stigmas.
This species is a member of subgenus Philodendron, section Macrobelium, subsection Macrobelium. It would key to series Ecordata Croat, but may represent a new series because the blades lack etched minor veins on the adaxial surface. The species is characterized by its scandent habit; thick, ovate coriaceous blades (hence the epithet from the Latin ‘‘coriaceus’’) with a flat midrib much paler than the blade adaxially and often tinged red abaxially; and yellow-orange berries. Philodendron coriaceum is most easily confused with P. chrysocarpum, which has elliptic leaves and yellow-orange berries. However, P. chrysocarpum differs in having subcoriaceous blades, 3.4–4.8(–5.2)x longer than broad (in contrast to 1.6–2.3(–2.6)x longer in P. coriaceum), a broadly raised midrib that is slightly paler adaxially and much paler or purple abaxially, and a yellowish green-striate spathe (in contrast to a spathe that is red-violet on the tube in P. coriaceum).
Philodendron coriaceum is known in Colombia from the western slopes of the Cordillera Occidental from Tropical wet forest (T-wf) in the department of Chocó to Tropical rain forest transition to Premontane (T-rf/P) in the department of Valle, ranging in elevation from near sea level to 150 m. It is also known from Carchi and Esmeraldas provinces, Ecuador, in Tropical wet montane forest (TM-rf) from near sea level to 800 m of elevation. The new species has been collected growing in primary forest, regrowth forest, dense tidal forest, and montane wet forest.
Colombia and Ecuador. Known from the western slopes of the Cordillera Occidental from Tropical wet forest (T-wf) in the department of Chocó to Tropical rain forest transition to Premontane (T-rf/P) in the department of Valle, ranging in elevation from near sea level to 150 m. It is also known from Carchi and Esmeraldas provinces, Ecuador, in Tropical wet montane forest (TM-rf) from near sea level to 800 m of elevation.