Philodendron atabapoense G.S.Bunting

Long scandent herb. Stem soon weak-grey-brown, 2.3 cm diam. Internodes somewhat longer than thick. Cataphylls green, margins becoming ivory, sparsely dotted with wine colour, dorsally 2-keeled, caducous. LEAVES: Petiole firm to rigid, somewhat shorter than blade, 47-59 cm long and 1 cm thick, terete or ventrally slightly convex in the upper part, pale green, spotted with wine-colour above and in the upper part, which is 4.3-5 cm long, pinkish-wine and slightly asperous, the lower part sheathed for 2.5-6 (-12) cm. Leaf blade chartaceous, firm but brittle, up to 50-63 cm long and (20.5-) 23-30 cm wide, outline triangular-ovate, very wide 2-5 cm above the base of the midrib, from a length of 15 cm upwards, quickly attenuating and concaved margined, after that, slightly attenuate and concave-margined up to the apex which is usually obtuse with an acumen; below from the place where it is very broad to halfway on the posterior lobe it is barely narrowed; Posterior lobes more or less oblong, obtusely rounded towards the apex or slightly angular, at halfway, one 6.7-8.3 cm and the other 10.3-12 cm wide, separated by a sinus 15-18 cm long, mitriform in outline. Ca. 3 principal veins from the base, joined into a posterior rib, naked for 2.5-4(-5) cm in the sinus; Anterior lobe primary lateral veins sulcate, (4-)5-6 on each side, spreading at an angle of 70º-85º; Margin slightly undulate and pale-yellowish-pink margined (0.1 cm) adaxially dark green, glaucescent, eventually moderately glossy; Midrib flat, convex below, 0.6 cm wide, pale yellowish-green, and wine-spotted, posterior ribs flat, pale yellowish-green, venation firstly wine-coloured eventually green, green on both sides, barely glossy, midrib convex sparsely wine-spotted, primary veins prominent, minor veins subparallel. INFLORESCENCE: Peduncles in pairs, 10.5-14 cm long, green, purple spotted upwards. Spathe up to 16.7 cm long, tube elongate fusiform, 8.6 cm long and 2.1 cm thick, externally green with pink-wine margins (3-4 mm), internally intense cheey coloured, blade white. Spadix sessile, strongly oblique at base, 14.5 cm long, pistillate part 4 cm long and 1.3 cm thick, sterile staminate part, 3.5 cm long and 1.5 cm thick, fertile part 8 cm long and 1.15 cm thick. Pistillate flowers more or less ovoid-urceolate, ovary 8 (-9)-locular, locules 4-ovulate.