Commelinids
In plant taxonomy, commelinids (originally commelinoids) (plural, not capitalised) 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 being 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. In the Takhtajan system treated this as one of six subclasses within the class Liliopsida (=monocotyledons). It consisted of: Cronquist system. The Cronquist system treated this as one of four subclasses within the class  Liliopsida. It consisted of: 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.