The commelinids are a monophyletic group of monocotyledonous flowering plants recognized in modern classification systems. The name is written in lower case and treated as a plural noun (commelinids). Molecular phylogenetic studies, as incorporated in the Angiosperm Phylogeny Group (APG) classifications, support the commelinids as a distinct lineage within the monocots, set apart from several more basal monocot lineages.
Key characteristics
Members of the commelinid clade share a mix of biochemical and anatomical characters alongside DNA evidence. A frequently cited biochemical marker is the presence of cell wall-bound phenolic compounds (notably ferulic acid derivatives) that often fluoresce under ultraviolet light. Other common features can include particular arrangements of vascular tissue and aspects of flower and pollen structure, although diversity within the group is substantial and many traits are best understood in combination with molecular data.
Major groups included
- Poales — grasses and related families (Poaceae and allies)
- Arecales — palms (Arecaceae)
- Zingiberales — gingers, bananas and related ornamental and tropical plants
- Commelinales — dayflowers and relatives
These orders contain many familiar and economically crucial plants: cereals and forage grasses, edible palms and coconuts, staple fruits such as bananas, and numerous horticultural species.
History and naming
The term commelinids derives from the name of the family Commelinaceae, a representative group within the clade. It was adopted in recent decades as molecular phylogenetics clarified relationships among monocots, prompting taxonomists to recognize a formal clade that groups together these related orders. Systems such as APG II and later updates used the commelinids as a named clade to reflect these evolutionary relationships.
Importance and distinctions
Commelinids include many plants of global importance for food, materials and horticulture; grasses alone underpin most human cereal production. The clade is one of the most conspicuous plant lineages in open habitats and tropical forests. In classification discussions the commelinids are contrasted with the so-called "basal monocots," a paraphyletic set of monocot lineages that diverged earlier and are not grouped within this named clade. For an introduction to plant classification terms see plant taxonomy resources.
Notable facts: the commelinids are defined by a combination of molecular evidence and shared chemistry rather than a single obvious morphological trait, and their recognition has helped stabilize modern monocot classification.