Philodendron prominulinervium Croat

Terrestrial or hemiepiphytic; internodes 1-20 cm long, 2.1-2.8 cm diam., dark green, becoming brown, glossy, somewhat flattened on one side with 2 blunt to moderately acute ribs; cataphylls 26-28 cm long, medium green, moderately soft and acutely D-shaped, the margins weakly raised, persisting semi-intact at uppermost nodes, as a few fibers lower on stem; petioles (43-)60-86 cm long (averaging 72.5 cm), 9-13 mm diam. at middle, erect to erect-spreading, acutely D-shaped near apex, bluntly so further down, medium green, weakly glossy, sparsely and inconspicuously dark-lineate; blades ovate-triangular, broadly acuminate at apex, conspicuously cordate at base, 40-56 cm long, 25-44 cm wide (averaging 47 X 34.3 cm), 1.2-1.6 times longer than broad, 0.5-0.8 times length of the petioles, broadest near point of petiole attachment; upper surface dark green with a somewhat velvety sheen, lower surface slightly to moderately paler and semiglossy; anterior lobe 31-39 cm long, moderately thin to thinly coriaceous; posterior lobes 14-22 cm long, 10-15 cm wide, directed very slightly inward; sinus spathulate, 11-16 cm deep, 4-10 cm wide; midrib broadly concave and slightly paler above, narrowly rounded and slightly paler below; basal veins 8-10 pair, first 3 free to base, others coalesced, narrowly sunken and concolorous above, round-raised and paler below; posterior rib naked for 2-3 cm; primary lateral veins 5-8 per side, departing midrib at 45°-60° angles, ascending to margin, narrowly sunken and concolorous above, round-raised and paler below; minor veins weakly raised above, moderately distinct. INFLORESCENCES 1 per axil; peduncle 6-8 cm long, 3-5 mm diam., medium green, semiglossy, sparsely short white streaked near apex; spathe tube maroon inside, dark maroon-burgundy outside, ellipsoid, 5-6 cm long, 16-21 mm diam.; spathe blade maroon inside, tinged reddish on outside, 4-7 cm long, 1.5-2.5 cm wide; spadix erect; pistillate portion tapered, 3.6-4.0 cm long, 10-14 mm diam.; staminate portion cylindroid, 3-3.9 cm long, 7-12 mm diam.; sterile staminate portion ellipsoid, 1.5-1.9 cm long, 10-11 mm diam.; staminate flowers 0.8-1.5 mm long, 1.1-1.4 mm wide; sterile staminate flowers 2.2-3.0 mm long, 1.2-1.4 mm wide; pistils 2.4-2.7 mm long, 1.4-1.8 mm wide; stigma 0.4-0.6 mm diam.; locules 5 per ovary; ovules 16-20 per locule, in 2 series, 3-5 mm long. INFRUCTESCENCES erect; peduncle to 10 cm long, 10 mm diam.; spathe tube 7 cm long, to 3.5 cm diam.