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 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 critically endangered dwarf species endemic to the Plateau de Dogny in New Caledonia.[3] The basal chromosome number for Ptisanais2n=78, whereas the one count for Marattia in the strict sense is 2n=80.[4] The type species for the genus is Ptisana salicina, the type specimen of which was collected on Norfolk Island.[1]
^ abcMurdock, Andrew G. (2008). "A taxonomic revision of the eusporangiate fern family Marattiaceae, with description of a new genus Ptisana". Taxon. 57 (3): 737–755. doi:10.1002/tax.573007.
^Murdock, Andrew G. (2008). "Phylogeny of marattioid ferns (Marattiaceae) inferring a root in the absence of a closely related outgroup". American Journal of Botany. 95 (5): 626–641. doi:10.3732/ajb.2007308. PMID21632388.
^Hassler, Michael. "World Plants: Ferns and Lycophytes list". World Ferns. Synonymic Checklist and Distribution of Ferns and Lycophytes of the World. Retrieved 25 June 2024.
