structural:expansion
Taxonomy

The taxonomy of this family is in constant flux, as new studies continue to clarify the relationships between species and groups of species, allowing more taxa at several ranks to be recognized. The Orchidaceae is currently placed in the order Asparagales by the APG III system of 2009.

Five subfamilies are recognised. The cladogram below was made according to the APG system of 1998. It represents the view that most botanists had held up to that time. It was supported by morphological studies, but never received strong support in molecular phylogenetic studies.

In 2015, a phylogenetic study showed strong statistical support for the following topology of the orchid tree, using 9 kb of plastid and nuclear DNA from 7 genes, a topology that was confirmed by a phylogenomic study in the same year.