Description from Flora of China
Trees, dioecious (?sometimes monoecious), deciduous; stipules minute, very early caducous. Leaves alternate; petiole elongate, sometimes with glands at apex or along length; leaf blade pinnate-veined, 3-veined from base, margin obtusely glandular-serrate. Flowers hypogynous, unisexual, in terminal or axillary, few flowered panicles or racemes; bracts present; pedicels articulate, with a pair of ± persistent bracteoles just below articulation. Sepals 5, nearly free, valvate, ovate, with base often appearing strongly cordate when sepals erect, papery, inside with glands at base near margin, margins conspicuously conduplicate. Petals absent. Disk glands absent. Staminate flowers: stamens many, free, inserted on slightly domed receptacle; filaments filiform; anthers oblong or ellipsoid, connective usually curved, bringing both locules to face in same direction (toward periphery of flower); abortive ovary very small. Pistillate flowers: smaller than staminate flowers; staminodes many, surrounding ovary base, resembling stamens but reduced; ovary 1-loculed; placentas 3 or 4, filiform, finally woody, persistent; ovules numerous; styles 3 or 4, very short; stigmas erect, spreading or strongly reflexed against ovary, flattened, irregularly 3-lobed. Capsule fusiform or narrowly ovoid, large, 3-valvate, outer layer of pericarp thin, dehiscent, inner layer thin, woody, persistent, valves characteristically splitting from apex and base and remaining attached by persistent woody placental strips; styles caducous. Seeds many, arranged vertically, compressed-flat, winged; wing flat, papery, not encircling seed, instead extending from one end only; seed proper small.
In fruit, forms of Carrierea calycina with smaller capsules can be difficult to distinguish from C. dunniana. The leaf length-to-width ratio can be helpful.
Two species: China, Vietnam; two species (one endemic) in China.