Stem cylindric, dull, green at the apex, becoming pale brown, 2.0-2.5 cm in diameter. Internodes 2.0-3.0 cm long. Roots adventitious, 0.2-0.3 cm in diameter, from reddish brown to red, turning brown with the passing of time. Prophyll (3.5-) 15.3-20.0 cm long, and 4.0-5.0 cm wide at the base, somewhat persistent, green when young, with shades of carmine, principally at the base, and with sparse carmine nectaries, becoming straw colored to brown with time. LEAVES: Petiole greenish, dull with wine-coloured extrafloral nectaries, becoming purplish or forming only one distinct purple ring at the junction with the leaf, (28.0-) 33.0-40.0 cm long and 0.5-0.6 cm in diameter, spongy, flattened on the upper surface and rounded on the lower side, with darker to purplish stripes, more frequent at the apex. Leaf blade slightly coriaceous, (27.0) 37.0-55.2 cm long and (9.2-) 10.5-11.0 cm wide, narrowly elliptic to oblong-lanceolate, cuneate to rounded at the base, discoloured green when young; upper surface dull green to slightly glossy and slightly rugose, corresponding with the fine venation; the lower surface slightly glaucescent and dull when adult. Midrib slightly convex on the upper surface, pronouncedly prominent on the lower surface and paler than the blade on both surfaces, sometimes concolorous on the upper surface or on both faces and displaying nectaries on both faces or only the lower face. Primary lateral veins absent. INFLORESCENCES: Floral sympodium with only one inflorescence. Peduncle (17.0-) 21.5-23.5 cm long and 1.3 cm in diameter, green, slightly glossy with darker striations and small sparse purple and wine-coloured nectaries. Spathe erect, 9.0-15.0 cm long, green externally with small sparse nectaries, tube 4.5 cm long and 2.5 cm wide, carmine internally, blade 10.0 cm long and 1.7 cm wide, white to yellowish white with white spots internally. Spadix 7.5-11.5 (-14.5) cm long, stipe 0.7 cm long; female zone 2.2-2.7 cm long and 1.5 cm in diameter, light green (yellowish - Martinelli 12972 et al.); male fertile zone cream to orange in post-floral condition, 6.2-11.1 cm long and 1.2-1.4 cm in diameter in the central region, presence of yellowish resin canals below the stamens; sterile male zone white 1.5-2.7 cm long and 1.4-1.8 cm in diameter. Stamens 4-6 per flowers, 2.0-3.0 mm long and 1.5-2.5 mm wide at the apex. Staminodes with resin canals at the base, 3.0-4.0 mm long and 2.0-2.3 mm wide at the apex. Gynoecia 1.0-3.0 mm long and 1.0-2.5 mm wide, ovary white to cream, locules 6-7 (-8), ovules 14 per locule in two parallel ranks, placentation axile, stigmas lobed, number of lobes equal to the number of locules. INFRUCTESCENCE: Fruit young, 5.0 mm long and 4.0 mm wide, berries green at the apex and white from halfway to the base, stigma persistent, ferruginous.
Close to P. longilaminatum, P. crassinervium and P. glaziovii, all pertaining to subgenus Philodendron section Baursia, which is characterised by the absence of primary lateral veins, the presence of stigmatic lobes, axile placentation and numerous ovules. P. longilaminatum is known just from the region of Mata Atlantica in the states of Bahia and Pernambuco, having a narrowly sulcate petiole, occurring in restinga and humid forest with altitudes up to 200 m, whereas in P. edmundoi the petiole meets flat with the upper surface, and occurs above 800 m. It differs from P. crassinervium by possessing a much less robust midrib, longer and wider leaves and a longer petiole, and from P. glaziovii differing by the absence of a sterile male zone on (the apex of) the spadix, by the larger number of ovules arranged in two series extending the whole of the locules, and by the longer length of the peduncle.