Hemiepiphytic; stem appressed-climbing, to 1 m long; internodes gray-green, glossy to semiglossy, 1-4(9) cm long, 2-4 cm diam., usually somewhat flattened on one side, frequently with a short series of transverse ridges just below the nodes on both sides of the rounded portion of internodes, usually about as broad as long, or broader than long on flowering plants, sometimes slightly longer than broad; roots dark brown, slender, few per node; cataphylls moderately spongy, 18-27 cm long, sharply 2-ribbed (ribs to ca. 1 cm high), medium green, densely dark green short-lineate, deciduous, apic-ulate (apiculum >1 cm long) at apex. LEAVES erect, ± rosulate, somewhat clustered at or near stem apex; petioles 11-42 cm long, 0.7-2.6 cm diam., subterete, somewhat spongy, slightly flattened, bluntly and broadly sulcate midway, less so toward apex, more so toward base adaxially, surface medium green, semiglossy, with dark green ring around apex; blades oblong-elliptic to oblanceo-late-elliptic, subcoriaceous to coriaceous, somewhat to markedly bicolorous, semiglossy, acuminate, sometimes long-acuminate at apex, mostly acute to rounded, sometimes broadly subcordate, or sometimes truncate at base, 27-80 cm long, 7.5-25 cm wide (2.2-4(5) times longer than wide), (0.97-3.6 times longer than petiole), upper surface dark green, drying dark gray-green, lower surface much paler, yellow-green, drying yellow-green to yellow-brown; sinus (when present) to 2.5 cm deep; midrib flattened at base, slightly sulcate midway, broadly convex at apex and concolorous above, convex, short-green-lineate, paler than surface below; basal veins (0)1-3(4), all free to base; posterior rib lacking; primary lateral veins 8-14 per side, departing midrib at a 65-75° angle (45-55° angle at apex), ± straight to the margins, sunken above, convex and slightly paler than surface or darker than surface below; interprimary veins flat, darker than surface below; minor veins moderately distinct and fine below, arising from both the midrib and primary lateral veins. INFLORESCENCES 2-3 per axil; peduncle 5.5-21(25) cm long, 8-12 mm diam., pale to medium green, finely white- or dark-striate; spathe (10.6)12-23 cm long, 1.7 cm diam. (0.7-2.6 times longer than peduncle), constricted midway above the tube, white to pinkish throughout, margins cream; spathe blade creamy white to yellowish green with faint green tinge along center on backside (B & K yellow-red 7.5/9), yellow-orange striate outside, 8.5-9 cm long (opening elliptic in face view, 7.5-9 cm long, 2-5.5 cm wide), pale green to white inside; resin canals orange; spathe tube oblong-ellipsoid, medium to dark green, sometimes weakly tinged purplish along margins outside, densely short white-lineate, semi-glossy outside, 5.5-10.5 cm long, 1.8-4 cm diam., bright red-violet to dark maroon (weakly so toward apex) to yellowish orange, sometimes broad, white-lineate or orange striate inside; spadix weakly stipitate to 3-5 mm long, cylindrical to weakly tapered, 7.5-15.3 cm long, broadest below the middle; pistillate portion cylindrical to clavate, pale lime green to pale yellow to medium or dark green, 3-5.5 cm long in front, 1.7-4 cm long in back, 1- 1.2 cm diam. at apex, 1.5 cm diam. at middle, 8- 11 mm wide at base; staminate portion 4.5-10.7(12) cm long; fertile staminate portion broadest in middle, slightly tapered toward both ends and broadened before the sterile portion, 9-16 mm diam. at base, 9-10 mm diam. at middle, 5-10 mm diam. ca. 1 cm from apex, broadest at the base, as broad as the pistillate portion, narrower than the sterile portion; sterile staminate portion broader than the pistillate portion, white, 8-15 mm diam.; pistils 1.7-3.2 mm long, 1.3-2 mm diam.; ovary 5- 8(9)-locular, 1.4-2.3 mm long, 1.5-2 mm diam., with sub-basal placentation, walls embedded with granular, crystal-like particles; locules 1.4-2.1 mm long, 0.3-0.5 mm diam.; ovule sac 1-1.2 mm long; ovules 1-2(4) per locule, contained within transparent, gelatinous ovule sac, 0.4-0.5 mm long, longer than funicle; funicle 0.1-0.5 mm long (can be pulled free to base), style 0.4-1.4 mm long, 0.9- 2.1 mm diam., similar to style type B; style apex sloping to rounded, with small medial depression; stigma brush-like, cupulate, subdiscoid, 0.9-1.2 mm diam., 0.2-0.6 mm high, covering entire style apex; the androecium truncate, prismatic, oblong, margins irregularly 4-6-sided, 1.3-1.4 mm long, 1.6-1.8 mm diam. at apex; thecae oblong to cylindrical, 0.4-0.5 mm wide, nearly contiguous and ± parallel to one another; pollen ellipsoidal to spheroidal, <1 mm long, <1 mm diam.; sterile staminate flowers irregularly 4-5-sided, margins bluntly rounded, 1.2-1.9 mm long, 1.8 mm wide. INFRUCTESCENCES: Berries orange (mature) or white; seeds 5 per berry, 1.3- 1.9 mm long, 0.5-0.7 mm diam.
This species is recognized by its ap-pressed-climbing habit; short internodes; more or less rosulate habit; somewhat spongy, subterete petioles; oblong-elliptic to oblanceolate-elliptic, dark gray-green-drying blades with mostly narrowly rounded bases, and two to three inflorescences per axil; and white to pinkish spathes clearly demarcated from the peduncles. Philodendron pseudauriculatum is most easily confused with P. ligulatum, especially P. ligulatum vars. heraclioanum and ligulatum, which have similarly shaped blades. Philodendron ligulatum var. heraclioanum differs in having sharply D-shaped petioles with undulate-margined wings. While the aforementioned varieties of P. ligulatum differ in their usually vining habit and typically elongate internodes, these features are particularly apparent in P. ligulatum var. ligulatum, which has inter-nodes much longer than wide (vs. about as long as broad or scarcely longer than broad as in P. pseudauriculatum). In addition, the leaves of P. ligulatum frequently dry much darker, mostly somewhat blackened, rather than the typical yellowish or brownish green of P. pseudauriculatum. Another feature separating live material of the species is the line of demarcation at the apex of the petiole, which is purple in P. ligulatum rather than green as in P. pseudauriculatum. Philodendron pseudauriculatum may also be confused with both P. auriculatum (hence the epithet "pseudauriculatum"), from the Pacific slope of southwestern Costa Rica and P. wendlandii Schott from the Atlantic slope of Costa Rica and Panama. Philodendron auriculatum is distinguished by having leaf blades drying a paler yellow-green color and more narrowed toward the base with minute narrow auriculate posterior lobes. It also has proportionately somewhat longer petioles. Philodendron wendlandii differs in having a much shorter stem and petioles typically broader than thick with sharp margins.
Definitely known only from Panama and adjacent Colombia (N Antioquia). Most collections have been made at La Mesa (Code), Cerro Campana (Panama), and along the El Llano-Carti Road (Panama), but the species is also known from a single collection in Bocas del Toro ,and in the Serrania de Canasas along the Pacific Ocean.