Hemiepiphyte or epiphyte; internodes ± terete, (1.5–)6–12 cm long, 1–2.5 cm diam., medium green and weakly glossy, becoming light yellow-brown and semiglossy; cataphylls to 20 cm long, medium green, semiglossy, sharply 1-ribbed below middle, sharply  2-ribbed toward apex, prominently purple-spotted at base, deciduous. Leaves  spreading; petiole thicker than broad,  narrowly rounded abaxially, sharply and deeply sulcate above sheath, 11–48 cm long, sheathed 9–17.5 cm, medium green, weakly glossy, matte and dark green short-lineate toward apex, weakly glossy and purple-spotted near base; blade narrowly ovate-elliptic, tapering towards the apex and ending with a short acumen, truncate at the base with the larger leaves becoming sagittate, 21–48 cm long, 7.5–24 cm wide, averaging 32 × 14 cm, 2–2.9 × longer than wide, 1.2–2 × longer than petiole,  subcoriaceous, dark green and semiglossy above, paler and glossy below; midrib slightly paler, flattened at base, broadly  convex toward apex above, paler and purple spotted, narrowly rounded, thicker than broad below; primary lateral veins 12–15 pairs, rising at 60–70° angle, weakly quilted-sunken and concolorous above, convex and dark purple below; minor veins fine, moderately obscure below; basal veins 3–4 pairs, all free to the base. Inflorescence 1 per axil; peduncle 4–6 cm long, whitish, obtusely flattened; spathe 10–15 cm long, 1.3 cm diam. on tube, pale green and matte to weakly glossy outside, greenish white  throughout inside except dark red-purple in lower 1/3 of tube, glossy with orange resin canals in lower 2/3 of spathe (those on coloured part whitish); spadix 12 cm long, female part 5.3 cm long in front, 3.7 cm long in rear, pale yellow-green; pistils 1.5 mm long, 1.5 mm diam.; stigma 0.2 mm thick, 0.6 mm diam.; locules 5; ovules 2 per locule, borne in oblong-elliptic transparent  mucilaginous sacs; placentation basal.

• A
• 2

Philodendron cardonii is a member of P. subg. Philodendron, probably a member of sect. Macrobelium, but further classification is not possible without further studies. It is characterised by its elongated internodes, its narrowly ovate-elliptic leaves, which are truncate or sagittate at the base, have 12–15 pairs of primary lateral veins and 3–4 pairs of basal veins all free to the base, and its  spathe, which is pale green outside and dark red-purple inside the lower part of the tube.

• A
• 2

Tropical wet forest life zone.

• A
• 2

Endemic to Colombia (Antioquia) in the valley of Río Claro.

• A
• 2