Elements of the Zingiberidae ( 2 orders, 9 families, 3,800 species) are often associated with order of the Commelinidae and Liliidae. Cronquist's treatment deals with the fact that these plants are "discordant" when so treated, i.e., the Bromeliales does not 'fit' well within the Commelinidae and the Zingiberales are a bit anomalous within the context of the Liliidae. Excluding both orders from these subclasses serves to "sharpen" the definition or circumscription of both. It does, however, create a unit that is not recognized by other current systems of flowering plant classification.
1. Epiphytes or xerophytes with narrow, parallel-veined leaves that are often leathery ant not petiolate, stamens 6, flowers usually actinomorphic.................... Bromeliales (monotypic)
2. Mesophytes of the forest floor or emergent aquatics with broadly expanded, petiolate leaves that carry a distinctive pattern of veination, stamens often 1 or 5 (rarely 6), flowers usually zygomorphic.....................Zingiberales