Description from Flora of China
Trees dioecious. Leaves often crowded near ends of branches, estipulate. Flowers unisexual, usually in heads or short racemes, in axil of a bract with 2 bracteoles. Male flowers 5-merous. Stamens 10, arranged in two alternate whorls; filaments linear; anthers 2-celled, dorsifixed, with lateral lengthwise slits; disk pulvinate. Female flowers (4 or)5-merous; staminodes usually present. Ovary inferior, 1(or 2)-loculed, 1-ovuled; style bifid, with stigmatic tissue at inside of stylar arms. Fruit drupaceous, ± laterally flattened, with persistent calyx and disk. n = 22 [in Nyssa javanica (Blume) Wangerin (Mehra & Bawainin, Evolution 23: 466-481. 1969)].
According to C. Q. Zhang (pers. comm.), most Chinese species of Nyssa are endangered and some of them may already have become extinct.
About 12 species: four in North America, one in Costa Rica, one from India to Malaysia, and seven (five endemic) in China.