Eugeissona is a clustering genus of flowering plant in the palm family native to Borneo, Thailand and Malaysia. The six monoecious species provide a wide range of local uses and are commonly called bertam or wild Bornean sago. The genus is the sole representative of the Eugeissoninae having very few obvious relatives; the hermaphrodite and staminate flowers are also found in Metroxylon, however the other specialized characteristics are unique suggesting an early split and differentiation from other members of the Calameae. Fossilized pollen belonging to these plants has been recovered in the lower and middle Miocene deposits in Sarawak. The name is from two Greek words meaning "good" and "roof", due to their common use in roof thatching.