Burmanniaceae

The APG II system of 2003,[6] as a result of an extensive study by Caddick and colleagues (2002),[7][8] using an analysis of three genes, rbcL, atpB and 18S rDNA, in addition to morphological criteria, led to a considerable rearrangement of the families within Dioscoreales.

According to these researchers the constituent clades are as follows: Burmanniaceae sensu stricto Afrothismia clade Tribe Thismieae But because of conflicting evidence, the APG IV (2016) authors[13] felt it was still premature to propose a restructuring of the order since the most recent evidence upholds the APG configuration and the work of Caddick and colleagues.

[14] According to molecular analyses, the myco-heterotrophic type of life that these species lead evolved six (or even more) times independently in the three clades that are part of Burmanniaceae.

Afrothismia and tribe Thismieae represent two of these shifts to myco-heterotrophy from autotrophy while Burmanniaceae sensu stricto are the clade where the other four took place.

The family appears in the Late Cretaceous but the further diversification and shifts to the typical habit occurred later in the same period and continued after the K-T boundary in Paleogene.