Terrestrial, helophytic, epilithic or epiphytic shrub. Stem robust, internodes 0.2-0.5 x 8-12 cm. Prophyll deciduous, 44-46 x 5.5-7 cm. Petioles 60-71 x l.5-2 cm, flattened to slightly convex adaxially, sheath 17-20 cm. Leaf blade bipinnatilobed, rarely pinnatilobed, 70-91 x 50-57 cm, adaxial surface shiny green, adaxial surface paler, primary nerve round abaxially, secondary nerves 4-5 per side, arising at an angle of 55-60°, lobes sublinear to spathulate. Posterior division 42.5-6 x 50-57 cm, basal nerve denuded for 6.5-7 cm, basiscopic nerves 2-3, acroscopic 2. Inflorescence solitary, peduncle 3- 6 x 3-4 cm, spathe green outside, white inside, 19-21 x 4.5-5.5 cm, apiculate at apex; spadix 12-17 cm long, fertile male portion round at apex, 5-6.5 x 1.6-1.8 cm, sterile male portion 6.5-8 x 2.7-2.9 cm, female portion 2-2.5 x 1.5-1.8 cm, adnate to the spathe for 60% of its length. Stamens prismatic, 5-6 x 1 mm, staminodes clavate, 4-6 x 1 mm, gynoecium 3-5 x 2.5-3 mm, stigma lobate, style slightly constrict, locules 8-11, 3-4-ovulate. Berries yellow, 12-28 x 4-6 mm, seeds ovoid, 3-3.5 X l.5- 2 mm.
Stem erect, subflexuous, rooting occasionally, 6 feet high, covered with dense, dark white, elliptic rhomboid leaf scars on the stem. LEAVES: Petiole terete, somewhat flattened on the upper surface, canaliculate at the base, 90-120 cm long; Blade 45-50 cm long, 50-60 cm wide, coriaceous, dark green and glossy on the upper surface, cordate-ovate in outline, bipinnatipartite, basal sinus deep, very open; primary lobes ca. 10, lanceolate or elliptic-lanceolate, up to 3-4-laciniate, lacinia [slash] narrow, gradually acuminate to the apex, rather obtuse, middle [one] very long, rather acute, terminal lobe bilobed or trilobed, lobes obtuse, primary veins strongly prominent, spreading almost at right angles from the midrib, barely reaching the apex, secondary veins very slender, very numerous, sub-parallel. INFLORESCENCE: Peduncle very short. Spathe ca. 25 cm long, externally green, internally white, boat-shaped, the tube barely distinct from the blade, apex apiculate. Spadix cylindric, firstly included, thereafter long-stretched out, bent back and overtopping the spathe; female zone 5-6 cm long, dorsally adnate to the spathe for 2/3 its length, sterile male zone 12-13 cm long, fertile zone 10-11 cm long, somewhat more slender than the sterile zone. Pistils prismatic, stigma thick, sessile, 6-7 mm long, 14-16 locular, locules 5-6-ovulate. Staminodes subclavate, 6 mm long. Stamens 8 mm long, yellow, oblong; seeds pale, oblong.
Philodendron lundii is quite variable ecologically, occurring as a helophyte, hemiepiphyte, epiphyte or epilith, from Central Minas Gerais to Goias State. In limestone outcrops it usually occurs growing directly on rocks (or in small pockets of soil) or is hemiepiphytic in trees growing in larger soil pockets on the rock.