Cyanea calycina is an unbranched shrub that grows 1–3 meters tall. In juvenile plants, the stems are woody and muricate (covered with short, hard projections) but become scabrous or nearly smooth as the plant ages. The leaves are simple and alternate, with elliptic or oblanceolate blades measuring 15–60 cm long and 5.5–14 cm wide. Juvenile plants have muricate upper leaf surfaces, which become glabrous in mature plants. The lower surfaces are densely pubescent with branched and clustered hairs. Leaf margins are callose-crenulate, becoming coarsely callose-dentate in juvenile leaves. Petioles are 1–9 cm long and either pubescent or muricate. It produces 4–16–flowered inflorescences in axillary positions, with peduncles 20–100 mm long and pedicels 5–30 mm long. The hypanthium is obovoid, obconical, or ellipsoid, 6–12 mm long, and pubescent. The flowers are perfect, featuring oblong to ovate calyx lobes and a zygomorphic (bilaterally symmetric) corolla that is pale to dark magenta or rarely pale greenish, often with longitudinal stripes, 5–8 cm long and pubescent. The staminal column is glabrous or pubescent, with pubescent anthers that may have apical tufts of white hairs. The ovary is inferior and 2-celled, leading to a 2-lobed stigma that becomes receptive after the anthers release pollen into the staminal tube. The fruits are obovoid to obpyriform berries, 16–20 mm long, containing numerous small, brown to black smooth, shiny seeds, ca. 0.2 – 0.5(-2) mm long, with a straight, short to spatulate dicotyledonous embryo embedded in oily endosperm. It is native to mesic valleys and wet forests, found at elevations between 300-915 meters.