Ptisana

Ptisana is a genus in the eusporangiate fern family Marattiaceae, comprising species historically treated in the genus Marattia. The establishment of this genus follows the 2008 work by Andrew G. Murdock, which supported recognition of this group on the basis of genetic analysis and morphology.[1][2] Ptisana can be distinguished from Marattia by the presence of distinct sutures at the point of leaflet attachment, deeply cut synangia, and the absence of labiate sporangial apertures. The name Ptisana is derived from the Latin word for pearl barley, an allusion to the shape of the synangia.[1]

Ptisana
King fern, Ptisana salicina
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Class:	Polypodiopsida
Order:	Marattiales
Family:	Marattiaceae
Genus:	Ptisana Murdock
Species
See text.

Sori of Ptisana fraxinea

Ptisana has a palaeotropical distribution, with the westernmost extreme of the range in Ascension Island and extending eastward through tropical Africa, Asia, and Oceania. Ferns in this genus are generally quite large, with fronds often reaching 2-3 meters in length; the one known exception to this is Ptisana rolandi-principis, a dwarf species endemic to the Plateau de Dogny in New Caledonia. The basal chromosome number for Ptisana is 2n=78, whereas the one count for Marattia in the strict sense is 2n=80.[3] The type species is Ptisana salicina.