Ptisana
Introduction Sori of ''Ptisana fraxinea'''''''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. ''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. ''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. The basal chromosome number for ''Ptisana'' is ''2n=78'', whereas the one count for ''Marattia'' in the strict sense is ''2n=80''. The type species for the genus is ''Ptisana salicina,'' the type specimen of which was collected on Norfolk Island.
Species *''Ptisana africana''  Christenh. – East Africa*''Ptisana ambulans'' Murdock & C.W.Chen – Solomon Islands*''Ptisana attenutata'' (Labill.) Murdock – New Caledonia*''Ptisana boivinii'' (Mett. ex Kuhn) Senterre & Rouhan – Madagascar*''Ptisana boninensis'' (Nakai) Yonek. – Bonin Islands*''Ptisana costulisora'' (Altson) Murdock – New Guinea and nearby islands*''Ptisana decipiens'' Murdock & C.W.Chen – Solomon Islands*''Ptisana fraxinea'' (Sm.) Murdock – Africa to India, including Indian Ocean islands*''Ptisana grandifolia'' (Copel.) Murdock – New Guinea*''Ptisana howeana'' (W.R.B. Oliver) Murdock – Lord Howe Island*''Ptisana kingii''  (Copel.) Christenh. – New Guinea*''Ptisana koordersii''  (Alderw.) Christenh. – Sulawesi*''Ptisana laboudalloniana'' Senterre & I.Fabre – Seychelles*''Ptisana melanesica'' (Kuhn) Murdock – New Guinea and nearby islands*''Ptisana mertensiana'' (C. Presl) Murdock – Micronesia*''Ptisana novoguineensis'' (Rosenst.) Murdock – New Guinea*''Ptisana obesa'' (Christ) Murdock – New Guinea*''Ptisana odontosora'' (Christ) Senterre & Rouhan – Guinea*''Ptisana oreades'' (Domin) Murdock – northern Australia*''Ptisana papuana'' (Alderw.) Murdock & C.W.Chen – Solomon Islands*''Ptisana pellucida'' (C. Presl) Murdock – Malaysia and the Philippines*''Ptisana platybasis'' (Copel.) Murdock – New Guinea*''Ptisana purpurascens'' (de Vriese) Murdock – Ascension Island*''Ptisana rigida'' (Alderw.) Murdock – New Guinea, Sulawesi*''Ptisana robusta'' (Altson) Senterre & I.Fabre – São Tomé*''Ptisana rolandi-principis'' (Rosenst.) Christenh. – New Caledonia*''Ptisana salicifolia''  (Schrad.) Senterre & Rouhan – South Africa, Zimbabwe, Malawi and Mozambique*''Ptisana salicina'' (Sm.) Murdock – king fern; South Pacific islands, including New Guinea*''Ptisana sambucina'' (Blume) Murdock – Malesia and Vietnam*''Ptisana senterreana''  Christenh. – Cameroon, Gabon, Equatorial Guinea*''Ptisana smithii'' (Mett. ex Kuhn) Murdock – Vanuatu, Fiji, Samoas, Tonga*''Ptisana soluta'' (Compton) Murdock & Perrie – New Caledonia*''Ptisana squamosa'' (Christ) Murdock – New Guinea*''Ptisana sylvatica'' (Blume) Murdock – Malesia*''Ptisana ternatea'' (de Vriese) Murdock – Moluccas, New Guinea, the Philippines*''Ptisana wernerii''  (Rosenst.) Christenh.Phylogeny of ''Ptisana''
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