Perrottetia wichmaniorum is a sprawling, dioecious small tree or shrub reaching 1.5–3 meters in height, typically with a dense crown. Its branches are green when fresh, sometimes tinged with purple or maroon, and are densely covered in pale brown villous-hirtellous hairs 0.2–0.5 mm long. The leaves are simple and spirally arranged, with broadly elliptic, broadly ovate, or suborbicular blades measuring 7–18.5 cm long and 4.5–10.5 cm wide. Leaf apices are acute to rounded with a short acuminate tip, and bases are broadly cuneate to truncate. The blade is thickly chartaceous to subcoriaceous, dark green above and often tinged purple or maroon along the veins and petioles. The upper surface is glabrous and rugose due to impressed venation, while the lower surface is prominently veined. Leaf margins are serrate-dentate with indurated teeth 0.5–1 mm long. Petioles are 1.5–5 cm long, brown villosulous or glabrous. Stipules are linear-oblong, 2–2.4 mm long, glabrous, and deciduous. Inflorescences are axillary or occasionally infrafoliar, forming pyramidal paniculate cymes with four orders of branching and a purple or maroon tinge. Staminate inflorescences measure 12.5–14 cm long and 10–13 cm wide, while pistillate inflorescences are 9–13 cm long and 6–13 cm wide, both with 2–4 cm long peduncles. Inflorescence axes are densely rufous-hirtellous with 0.2–0.3 mm long hairs. Bracts are glabrous, ovate-elliptic to subulate, decreasing in size along the branching order. Flowers are borne on glabrous pedicels 0.5–1 mm long, hirtellous below the articulation. Staminate flowers spread at anthesis and have purplish green, ovate sepals 1.0–1.2 mm long with acute to acuminate apices. Pistillate flowers, which do not spread at anthesis, have reddish purple, ovate-deltate sepals 1–1.4 mm long. Pistillate and staminate flowers have five white, glabrous, ovate petals similar in size to the sepals. Staminate flowers possess five stamens with 2–2.5 mm long filaments and transverse-ellipsoid anthers 0.5–0.6 mm long and 0.6–0.7 mm wide. Pistillate flowers have five staminodes 0.3–0.4 mm long and a superior ovary with a conical pistil 1.2–1.5 mm long and 2(–3) papillose stigma lobes. Staminate flowers include a pistillode 0.8–1.0 mm long. The fruit is a globose, glabrous berry 2.5–4 mm in diameter, ripening red or tinged purple. Infructescences measure 8–14.5 cm in length and 6–14 cm in width. Each fruit contains 2–4 tan, subglobose seeds, approximately 1–2 mm long, with a rugose-reticulate seed coat surrounded by a thin aril. It occurs on windward upper valley slopes, streambanks, and summit areas in mesic to wet forest environments, between 740-1,280 meters.