Peperomia macraeana is a fleshy herb with stems that are usually red, erect, or ascending from a short repent base, stout, measuring 50–200 cm long and about 5–25 mm in diameter toward the base. The stems can be branched usually above the middle or sometimes unbranched, with internodes 4–15 cm long, glabrous to moderately hirsute, appressed hirtellous, or a mixture of the two types, with hairs 0.3–1 mm long. The leaves are simple, opposite, or whorled, with 2–4 (occasionally up to 8) per node. The blades are ovate to broadly ovate, elliptic-lanceolate, elliptic, or sometimes elliptic–obovate, measuring 5–15 cm long and 2–7 cm wide. The apex is acuminate to narrowly or broadly acute, and the base is cuneate, sometimes rounded or subcordate. The upper surfaces are glabrous or sometimes sparsely hirsute to appressed hirtellous along veins and toward the base. In contrast, the lower surfaces are sparse to moderately hirsute to hirtellous or glabrous, with upper surfaces dark green and lower surfaces red, with pale green veins. The leaves are thickened and firm–fleshy, drying to a chartaceous texture. The margins are flat and usually ciliate at least toward the apex. The leaves are usually pinnately 5-veined or 7-veined, with principal veins slightly to strongly impressed and tertiary veins visible and somewhat impressed. Petioles are 0.8–3 cm long, glabrate to hirsute or appressed hirtellous. Stipules are absent. The flowers are in spikes, usually several, terminal and axillary, stout, 3–7 cm long, with the rachis about 2–3 mm in diameter, glabrous, with densely congested flowers. Peduncles are 0.8–1.5 cm long, glabrate to hirsute or hirtellous. The flowers are bisexual (perfect) and lack a perianth, each subtended by a peltate bract. The calyx (sepals) and corolla (petals) are absent. Stamens are 2. The ovary is superior, turbinate to obovoid, 1-carpellate, 1-celled, with an oblique apex and 1–4 terminal stigmas. The fruit is narrowly obovoid, about 1 mm long, with a beaked apex, papillose–viscid with sessile glands. There is one seed per fruit, with scanty endosperm and copious starchy perisperm. It is found in wet forests between 610-2,080 meters.