Commelinids

In plant taxonomy, commelinids (originally commelinoids ) is a clade of flowering plants within the monocots, distinguished by having cell walls containing ferulic acid.

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 are the alismatid monocots and the lilioid monocots.

Description
Members of the commelinid clade have cell walls containing UV-fluorescent ferulic acid.

Taxonomy
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). 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.

Takhtajan system
The Takhtajan system treated this as one of six subclasses within the class Liliopsida (=monocotyledons). It consisted of the following:

subclass Commelinidae superorder Bromelianae order Bromeliales order Velloziales superorder Pontederianae order Philydrales order Pontederiales order Haemodorales superorder Zingiberanae order Musales order Lowiales order Zingiberales order Cannales superorder Commelinanae order Commelinales order Mayacales order Xyridales order Rapateales order Eriocaulales superorder Hydatellanae order Hydatellales superorder Juncanae order Juncales order Cyperales superorder Poanae order Flagellariales order Restionales order Centrolepidales order Poales

Cronquist system
The Cronquist system treated this as one of four subclasses within the class Liliopsida. It consisted of the following:

subclass Commelinidae order Commelinales order Eriocaulales order Restionales order Juncales order Cyperales order Hydatellales order Typhales

APG system
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). The commelinids now constitute a well-supported clade within the monocots, and this clade has been recognized in all four APG classification systems.

Subdivision
The commelinids of APG II (2003) and APG III (2009) contain essentially the same plants as the commelinoids of the earlier APG system (1998). In APG IV (2016) the family Dasypogonaceae is no longer directly placed under commelinids but instead a family of order Arecales.