CUPULIFERAE, a group name used to include two families of familiar trees (Fagaceae and Betulaceae), which resemble one another in many features. The plants are trees or shrubs with simple leaves alternately arranged and small unisexual flowers gen erally arranged in catkins and pollinated by wind-agency. The generally one-seeded nut-like fruit is associated with the persistent often hardened or greatly enlarged bracts forming the so-called cupule which gives the name to the group.