Description from Flora of China
Dillenia hainanensis Merrill.
Deciduous trees to 15 m tall, to 1 m d.b.h. Bark smooth, gray, exfoliating; branchlets glabrous, stout. Petiole 2-5 cm, glabrous, with narrow wings; leaf blade oblong to obovate-oblong, 20-60 × 10-25 cm, leathery, secondary veins 25-50 on either side, margin with shallowly undulate teeth. Flowers 2-7, small, fascicled at top of lateral spurs, 2-3 cm in diam., less than 2 cm in diam. in bud; pedicels 2-4 cm, bractlets deciduous. Sepals 5. Petals 5, yellow, obovate. Stamens in 2 distinct groups, outer 60-90, 3-4 mm, slightly curved in bud, inner ca. 10, reflexed, 6-9 mm; anthers dehiscing with longitudinal slits.
Carpels 5 or 6, 3.5-4 mm in diam.; stylodia spreading; ovules 5-20 per carpel. Pseudocarp indehiscent, yellow, orange, or red; carpels each 1(or 2)-seeded. Seeds exarillate. Fl. Apr-May.
Rain forests, thickets, hills; below 400 m. Hainan, Yunnan [Bhutan, India, Indonesia, Malaysia, Myanmar, Nepal, Thailand, Vietnam].