Creeping or climbing vine; stems with colourless sap oxidising orange, rooting at the nodes; internodes short, 0.5– 3 cm long, to 6 cm diam., drying yellow-brown; cataphylls deciduous. Leaves erect; petiole subterete, 85–109 cm long, 1–1.5 cm diam. at the apex; blade ovate-sagittate, widest at level of petiole insertion and tapering towards the apex, short-acuminate at apex, deeply lobed at base, 58–101 cm long, 34–65 cm wide, 1.3–1.7 × longer than wide, 0.8–1 × as long as petiole, matte and drying dark olive-green; posterior lobes 24–40 cm long, 15–23 cm wide, curving inwards; sinus spathulate, 20–31 cm deep, 12–18 cm wide; midrib broad-flattened above, convex below, drying concolorous above, lighter than surface below; primary lateral veins 13–14 pairs, arising at 60–75° angle, slightly raised above and below; minor veins inconspicuous; basal veins 10–12 pairs, the first 2–4 pairs free to the base and the others branching on both sides of the posterior rib; posterior rib thick, free for 3–8 cm and projecting in a straight line into the centre of the posterior lobe. Inflorescences 1–5 per axil; peduncle 21–33 cm long, c. 8 mm diam., drying blackened; spathe 20–22 cm long, blade 3.5–7 cm wide, tube 3.5–4.5 cm diam., blade green outside, white inside, sometimes with orange longitudinal stripes, tube green outside, red or dark red-violet inside; spadix 18–21 cm long, 1.2–1.5 cm wide, white in male and sterile sections, light green in female section; pistils 1.6–1.8 mm long, 1–1.1 mm diam., style with a prominent central dome, stigma 1.6–1.8 mm diam., ovary 4–5-locular, locules 1-ovulate; ovules contained within a mucilaginous, very sticky, transparent sac, 0.8–1 mm long, the ovule proper oblong, c. 0.5 mm long, with a glandular funicle 0.3-0.4 mm long.
The species is a member of Philodendron subg. Philodendron sect. Macrobelium subsect. Glossophyllum series Ovata and is recognised by its hemiepiphytic habit, thick stem with short internodes, deciduous cataphylls, subterete petioles, its large matte, ovate-sagittate leaf blades with a well-developed posterior rib and 10–12 pairs of basal veins, as well as by up to 5 inflorescences per axil with long peduncles, the spathe tube green outside, red-violet inside and with the spathe blade green outside and white inside.
The Lucid key to Philodendron keys out P. dodsonii Croat & Grayum, P. grandifolium (Jacq.) Schott, P. pastazanum K. Krause, P. sagittifolium Liebm. and P. simmondsii Mayo for this species. P. dodsonii has a red spathe tube instead of the green tube in P. silverstonei; P. grandifolium is from eastern South America (Venezuela, Guyanas); P. pastazanum has peltate leaves instead of ovate-sagittate; P. sagittifolium has smaller and narrower leaves with small posterior lobes and does not have a well-developed posterior vein like P. silverstonei; P. simmondsii has blade margins that are distinctly sinuate andsilverstonei.