Philodendron popenoei Standl. & Steyerm.

Terrestrial plants, sprawling and clambering over ground or atop boulders, or becoming scantent and ascending trunks of trees to at least 5 m, the fertile branches divergent. Internodes 1.0-14.1+ cm long, to at least 1.5 cm wide, olive- to gray- green, matte to glossy, flattened on one side, drying yellowish, sulcate, the epidermis brittle and cracking; roots commonly absent from distal nodes, when present to ca. 2.5 mm in diameter. LEAVES: Petiole (20.9-) 22.6-38.5 (-44.7) cm long, P/L=0.77-1.11 (-1.35), matte to senmiglossy, sheathed (43-) 53-72 (-75)% , the sheath erect to involute, weakly greenish striate or whitish striate proximally, adnate distally or the free portion prolonged to 1.0 (-2.0) mm; unsheathed portion of petiole 7.4-12.5 (-17.4) cm long, terete (but slightly flattened above distally). Lamina (19.5-) 26.7- 36.6 (-42.9) cm long, (9.3-) 17.6-32.3 (-34.7) cm wide, L/W= (1.01-) 1.11-1.82 (-2.10), IQl=(0-) 1-4 (-5), thinly curvaceous to subcoriaceous, velvety-matte or weakly glossy to glossy above, matte below, virtually concolorous to moderately bicolored, broadly lanceolate to broadly ovate or suborbicular (widest below the middle), acute to short-acuminate apically (the acumen ca. 0.2-1.4 cm long), rounded-cordate basally with the sinus 0.4-1.8 (-3.4) cm deep; midrib flat or broadly sunken above and concolorous or slightly paler, convex and paler below; primary lateral veins 8-15 per side, ca. 1.3-4.9 cm apart, sunken and slightly paler above (at least proximally), convex or somewhat C-shaped below; interprimaries absent or obscure; minor veins distinctly visible below, darker and prominulous; abaxial laminar surface drying somewhat granular along the smaller lateral veins, with reticulate veins abundant throughout; white stitching and/or resin canals visible between the smaller lateral veins, the stitching following over the canals; adaxial surface abundantly granular along all veins, sparingly so on surfaces, with reticulate veins visible throughout (reticulate veins and especially granulations may be obscure on larger leaves); some white stitching visible, but no resin canals. INFLORESCENCES always solitary in Guatemalan and Honduran material, usually 2-3 in Costa Rican material; cataphylls infrequent or inconspicuous, ephemeral, 2.5-5.4 cm long, ca. 3-10 mm wide, blunt or rounded apically, obtusely 2-keeled; peduncle (2.2-) 3.6-5.3 (-10.2) cm long, P/S=0.37-0.51 (-1.06), medium green, bluntly angled, coarsely raised- whitish striate (especially distally); spathe at anthesis (9.4-) 11.1-13.6 cm long, 2.3- 2.8 cm wide, externally matte or weakly glossy, light green below, ochroleucous and densely fine-striate-lineate distally, internally uniformly cream-colored or pale greenish, weakly constricted ca. 5/12 from base; spathe drying densely and minutely granular on both surfaces, internally with very fine and closely subparallel longitudinal secretory striations from base to apex; acumen of spathe to at least 1.9 cm long. Stipe of spadix 0.3-1.0 cm long; cut axis of spadix pinkish; spadix 8.5-11.3 cm long, the fertile male portion 1.0-1.1 cm wide, cream-colored, slightly arched forward at female receptivity; sterile male zone 0.6-0.9 cm long; female portion of spadix 2.7- 4.2 cm long, F/S= (0.26-) 0.35-0.39, 1.1-1.2 cm wide, light green or yellowish; fertile male flowers 1.30-1.75 mm long, 0.6-1.2 mm wide, irregularly polygonal and somewhat laterally compressed; sterile male flowers 1.65-2.00 mm long, 0.85-1.20 mm wide, strongly laterally compressed, striate apically; female flowers 2.25-2.65 mm long, 0.7-0.9 mm wide, the stylar canals 4-6. INFRUCTESCENCES: Ripening fruits yellow-orange, yellow-brown, or orange-yellow. Seeds 0.6-0.9 mm (Croat to Grayum 59910, Grayum et al. 4771) to 1.3-1.6 mm (MacDougal et al. 3394) long, 0.15-0.30 mm wide, straight or slightly curved, finely striate with the striae finely cancellate, drying medium brown and semiglossy.