Trees evergreen, resinous. Leaves opposite or alternate, petiolate, estipulate, simple, margin entire or rarely undulate, leathery to thickly papery, often pubescent with unicellular 2-armed trichomes, pinnately veined. Inflorescences paniculate cymes, terminal and axillary. Flowers bisexual, actinomorphic, 4- or 5-merous. Petals distinct, valvate. Anthers dorsifixed, dehiscing via longitudinal slits; pollen 3-aperturate. Ovary inferior, carpel 1, locule 1; ovule 1, pendulous; disk epigynous, fleshy; style 1, stigma punctiform, unlobed, or lobes slight, 2, 4, or 5. Fruit drupes, fleshy, or hard when dry; endocarp grooved; seed 1, endosperm fleshy; cotyledons 2, leafy; embryo small.
Two genera and ca. 27 species: Bhutan, Cambodia, China, India, Indonesia, Laos, Malaysia, Myanmar, Papua New Guinea, Philippines, Sri Lanka, Thailand, Vietnam; Pacific Islands (Solomon Islands); two genera and four species (two endemic) in China.
Recent molecular analyses suggest that Diplopanax is the sister of Mastixia (Xiang et al., Molec. Phylogen. Evol. 24: 35–57. 2002; Fan & Xiang, Amer. J. Bot. 90: 1357–1372. 2003). The close relationship between the two genera is also supported by some morphological characters (see Eyde & Xiang, Amer. J. Bot. 77: 689–692. 1990). Thus, the genus is best placed in either the Mastixiaceae or the Cornaceae sensu lato. Eyde and Xiang (loc. cit.) moved Diplopanax to the Cornaceae sensu lato (i.e., including Nyssaceae and Mastixiaceae), and Murrell (Syst. Bot. 18: 469–495. 1993) treated it as a subgenus of Mastixia in the Cornaceae. We include it here in the Mastixiaceae.
Soong Tzepu. 1990. Mastixia. In: Fang Wenpei & Hu Wenkuang, eds., Fl. Reipubl. Popularis Sin. 56: 2–5; Hoo Gin & Tseng Chang-jiang. 1978. Diplopanax. In: Hoo Gin & Tseng Chang-jiang, eds., Fl. Reipubl. Popularis Sin. 54: 135–136.