Description from Flora of China
Trees evergreen, monoecious. Branchlets with solid pith, rarely with hollow pith probably due to ants. Terminal buds with false-valved scales. Leaves odd-pinnate; leaflets 7 or 9(or 11), margin entire. Inflorescences lateral or terminal on new growth; male and female inflorescences separate: male spikes in clusters of 5-8, lateral in axils of new foliage leaves, pendulous; female spike terminal on new growth, erect. Flowers anemophilous. Male flowers with an entire bract; bracteoles 2; sepals apparently absent; stamens 5-15, anthers pubescent. Female flowers with an entire bract adnate to ovary; bracteoles 3, adnate to ovary; sepals apparently absent; style possibly present; stigmas commissural, stigmatic disc apparently absent. Fruiting spike erect. Fruit a drupelike nut with a thick, 4-9-valved husk covering a smooth shell 2-chambered at base. Germination hypogeal.
This taxon has been variously placed in different genera. The authors of this account believe that Annamocarya has a number of uniquely derived characters not shared with Carya (e.g., prominent buttresses, entire leaflets, male spikes in clusters of 5-8, abaxial bundles of nut located in outer shell wall vs. in primary partition), and therefore warrants recognition at generic rank.
One species: SW China, N Vietnam.