Kadua cordata subsp. cordata is a subshrub that is usually few-branched. The stems are weakly erect to scandent, terete (cylindrical) to weakly quadrangular, rarely sharply so, and range from 1–6 meters long. The stems are glabrous and usually conspicuously glaucous. The leaves are simple and opposite, with blades that are ovate to broadly ovate, elliptic-ovate, ovate-cordate, elliptic-oblong, elliptic, or sometimes lanceolate, measuring 3–16 cm long and 2.3–7.5 cm wide. The leaf apex is acuminate to long-acuminate, and the base is broadly cuneate, rounded, subcordate, or occasionally attenuate. The surfaces are glabrous or hirtellous on the lower surfaces, sometimes mostly along the veins, and are glossy, thin, and membranous to thickened and subcoriaceous or sometimes coriaceous. The lower surfaces are usually also glaucous. The margins are entire and can be flat or revolute. The lateral veins are slightly to strongly impressed on the upper surface and slightly to conspicuously raised on the lower surface, with higher-order venation obscurely or sometimes conspicuously reticulate. The petioles are 0–1 cm long, with slightly connate bases. The stipules are deltate, usually carinate, 3–9 mm long, slightly connate, and adnate to the petioles, with an apex that has a slender mucro 2–5 mm long. The flowers are in terminal, compound, decussate, and paniculate inflorescences, usually composed of congested cymes that sometimes elongate monochasial and become open. The pedicels are quadrangular and 2–8(–15) mm long. The inflorescences are glabrous and usually strongly glaucous throughout, with bracts of the ultimate branches, and each flower is usually foliaceous and partly obscuring the flower, occasionally small and scale-like. The hypanthium is turbinate, 1.5–2.2 mm long. The flowers are bisexual (perfect) and pistillate, insect-pollinated, with a calyx that is 4–5-lobed, the lobes usually foliaceous, oblong-ovate to broadly ovate, 4–8 mm long, and 1.5–2.5 mm wide, enlarging somewhat in fruit. The corolla is pale green to greenish-yellow, greenish-white, or cream-colored, rarely tinged purple, fleshy, and usually glaucous, with a 9–17 mm long salverform tube. The lobes are 2.5–7(–10) mm long at anthesis, strongly inflexed in bud, and more or less revolute. The nectary disc is present. The stamens are as many and alternate with the corolla lobes, inserted about 1–3 mm below the corolla tube sinuses. The anthers are sessile or on short filaments, dithecal, and open by longitudinal slits. The ovary is inferior or partly so, 2(-4)-locular, with few to numerous ovules on fleshy placentas near the middle of the septum. The styles are as many as the carpels, cylindrical to filiform, terminal, slender, and woolly-villous in the lower two-thirds to one-third. The stigma is bilobed or subcapitate, included or exserted. The fruit is a capsule turbinate to subglobose, 2–4 mm long and 3–7 mm in diameter. The capsule dehisces loculicidally across the disk, with pyrenes tardily dehiscing septicidally. The endocarp is strong to sometimes thinly sclerified, with the disk flat to slightly raised. The seeds are dark brown, irregularly cuneiform, and irregularly angled, with a darkly granular to reticulate-pitted surface and well-developed oily endosperm. However, the endosperm is occasionally scanty or absent. It occurs in mesic to wet forests, sometimes on windswept ridges between 400-1,820 meters.