Terrestrial ferns of moderate to large size. Rhizome erect, stout and woody, bearing a compact apical crown of fronds, dictyostelic, naked, the stipe bases persistent, swollen and bearing stipular wings, the stipe with a single U-shaped vascular bundle. Fronds deltoid or lanceolate, the basal pinnae somewhat reduced, the apical pinna generally like the others, pinnate or bipinnate, the pinnae or pinnules free, the ultimate segments entire or serrate, costate, thick, the veins free, in +/- distinct groups, several-times forked, sometimes each group with a +/- distinct costule; whole fronds or only pinnae dimorphic, the fertile portions contracted and devoid of lamina. Sporangia not grouped into sori, crowded on short, spaced, little-branched lobes of the fertile pinnae, large, +/- globose, on short, thick stalks, dehiscing from the annulus over the apex, the annulus a group of thickened cells to one side, exindusiate, paraphyses absent. Spores trilete, globose, green.
Sect. Osmunda: fronds bipinnate, withering in winter; fertile fronds totally dimorphic, or with fertile apical pinnae.
Sect. Osmundastrum: fronds bipinnatifid, withering in winter; fertile fronds totally dimorphous, or with fertile lateral pinnae.
Sect. Plenasium: fronds pinnate with entire or serrate pinnae, evergreen; fertile fronds with fertile lateral, or basal and lateral pinnae. (O. banksii).
Species in Papuasia
|A single species in Papuasia...||O. banksii|