In plant taxonomy, commelinids (originally commelinoids[1][2]) (plural, not capitalised) is a clade of flowering plants within the monocots, distinguished by having cell walls containing ferulic acid.[3][4]
The commelinids are the only clade that the APG IV system has informally named within the monocots. The remaining monocots are a paraphyletic unit. Also known as the commelinid monocots it forms one of three groupings within the monocots, and the final branch, the other two groups being the alismatid monocots and the lilioid monocots.
The commelinids were first recognized as a formal group in 1967 by Armen Takhtajan, who named them the Commelinidae and assigned them to a subclass of Liliopsida (monocots).[5] The name was also used in the 1981 Cronquist system. However, by the release of his 1980 system of classification, Takhtajan had merged this subclass into a larger one, and no longer considered it to be a clade.
In the Takhtajan system treated this as one of six subclasses within the class Liliopsida (=monocotyledons). It consisted of:
The Cronquist system treated this as one of four subclasses within the class Liliopsida. It consisted of:
The APG II system does not use formal botanical names above the rank of order; most of the members were assigned to the clade commelinids in the monocots (its predecessor, the APG system used the clade commelinoids).[6][7] The commelinids now constitute a well-supported clade within the monocots,[8] and this clade has been recognized in all four APG classification systems.