Philodendron amplisinum G.S.Bunting

Scandent herb. Stem up to 3 m long, 4-7 cm thick, internodes decidedly short, naked except for the apex hidden by remaining dry and fibrous cataphylls. Cataphylls 22 cm long. LEAVES: Petioles solid, subterete, ventrally angular-convex, or flattened below, 65-98 cm long, 1.7 cm thick, black (when dry), sheathed region 4-7 cm long, geniculate distally for more or less 6 cm. Leaf blade chartaceous or subcoriaceous but brittle, outline broadly ovate 52-77 cm long, 46-57 wide, with large semicircular posterior lobes at the base, sinus hippocrepiform or spathulate, 15-20 cm long to 11 cm wide, separate or lobes rarely imbricate, sinus closed and obovate, broadly obtuse towards apex (100-140º), apex itself acuminate (4-5 cm), dark brown when dry, venation black, midrib 0.8 cm wide, primary lateral veins 5 (-6) on both sides, origination from the midrib at an angle of 35-50º, minor veins arising from below the primary lateral veins, ca. 5 robust veins in each of the posterior lobes, joined into a rib, naked for 5-8.5 cm in the sinus. INFLORESCENCES in pairs. Peduncle 16-18 cm long marked with pale interrupted striations sometimes reaching near the apex. Spathe 13-18 cm long, tube 5.5-8.5 x 2.5-4.3 cm externally dark green, limb externally pale green. Spadix; female zone (bearing fruit) 6-7.3 x 2.5 cm, sterile male zone 1.5 cm long, fertile zone subequal to the female zone. Pistillate flowers: ovaries 3-5 locular, ovules in each locule numerous, positioned at the top. Staminate flowers 5-4-androus. INFRUCTESCENCE: Berries 0.9 cm long.