Donatia

Donatia is a genus of two cushion plant species in the family Stylidiaceae. In the past, Donatia has been placed in the subfamily Donatioideae, described by Johannes Mildbraed in his 1908 taxonomic monograph of the family Stylidiaceae. The subfamily was created to distinguish the difference between the single genus Donatia from the five typical genera of the Stylidiaceae that Mildbraed placed in the Stylidioideae subfamily. The subfamily taxonomy represented the taxonomic uncertainty of Donatia, which had at one point also been placed in the Saxifragaceae. Donatia differs sufficiently from the genera in the Stylidiaceae in that it has free stamens and petals, paracytic stomata, and a pollen morphology distinct from the other genera. Because of this and the recent phylogenetic analysis based on rbcL genes, more recent treatments have segregated Donatia into its own family, the Donatiaceae. The molecular phylogenetic analysis has placed Donatia as a sister-group to Stylidiaceae, thus leaving the Stylidiaceae as a monophyletic family.