Christmas berry forms shrubs or trees 1-7 m tall and can be recognized by compound leaves, with leaflets arranged opposite one another, and terminal leaflets larger than lateral leaflets.  This plant is marked by white flower clusters and copious amounts of bright red fruits.  Schinus terebinthifolius is of South American origin and in 1909 was introduced to Hawai`i as an ornamental plant.  It has since become a major pest species in mesic and disturbed areas and is on the state's list of Hawai`i's most invasive horticultural plants.  S. terebinthifolus has become naturalized on Midway atoll and all main Hawaiian islands except Ni`ihau and Kaho`olawe.