Orchidales

The Orchidales used to be divided into the following families:

• Thismiaceae : is now considered a sister to and included in the family Burmanniaceae, which belongs to another order Dioscoreales.
• Orchidaceae - The orchid family is subdivided in several several subfamilies, and then in tribes, subtribes, alliances and then genera. The following six subfamilies are recognized :
• *Subfamily Spiranthoideae : (derived from Orchidoidea)
• *Subfamily Orchidoideae : considered paraphyletic; most orchids (750 genera)
• *Subfamily Epidendroideae : includes almost 80 % of the species; monophyletic
• *Subfamily Vandoideae : monophyletic
• *Subfamily Apostasioideae : monophyletic (Apostasia and Neuwiedia)
• *Subfamily Cypripedioideae : monophyletic; lady's slippers (4 genera)
• *Subfamily Vanniloideae, sometimes recognized as a distinct subfamily. But, from a molecular point of view, it is rather a sister to subfamily Epidendroideae + subfamily Orchidoideae. This subfamily is a branch at the basal dichotomy of the monandrous orchids.