1) Class 2) Subclass commelinidae 
Commelinidae is a botanical name at the rank of subclass. Circumscription of the subclass will vary with the taxonomic system being used (there are many such systems); the only requirement being that it includes the family Commelinaceae. A well-known system that did use this name is the Cronquist system (1981), but it was also used by the Takhtaja...
(from the article `angiosperm`) ...leaves. Two families, Araceae (arum) and Lemnaceae (duckweed), the latter consisting of small, free-floating plants of simple structure.Subclass ...
[n] - one of four subclasses or superorders of Monocotyledones
subclass Commelinidae noun one of four subclasses or superorders of Monocotyledones; comprises about 19,000 species in 25 families of mostly terrestrial herbs especially of moist places including: Cyperaceae; Gramineae; Bromeliaceae; and Zi...