The Arecidae is, perhaps, the most diverse flowering subclass in terms of both structural and ecological adapitations. This group of 4 orders, 6 families and about 5,600 species includes the smallest flowering plants (Lemnaceae - Arales), the largest monocots (Arecaceae - Arecales) and the largest flowering plant seeds (Lodoicea maldivica - Arecaceae) and leaves (Raphia regalis - Arecaceae).  More than half of the species of this subclass belong to the monotypic order Arecales.

Arecales
     Arecaceae(Palmae)
Arales
    Araceae
    Lemnaceae