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Osmundaceae

Incl. Todeaceae

Terrestrial ferns of moderate to large size, rhizome erect, stout and woody, sometimes tree-like, bearing a compact apical crown of fronds, dictyostelic, naked, the stipe bases persistent, swollen and bearing stipular wings. Fronds long stipitate, the stipe with a single U-shaped vascular bundle, lamina pinnate, or bipinnate to tripinnate-pinnatifid, veins free, simple, once- or several-times forked, sometimes arranged in pinnate groups, texture leathery to filmy, fronds uniform or whole fronds or only pinnae dimorphic, the fertile portions variously contracted. Sporangia not grouped into sori, crowded on fertile pinnae or on loose superficial clusters, exindusiate, 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.

Distribution

A more or less cosmopolitan family from most of the wetter tropical and temperate regions of the world, 3 genera with about 20 species. All 3 genera occur in Papuasia with 4 species.

Literature

Hennipman, E. 1968. A new Todea from New Guinea, with remarks on the generic delimitation of recent Osmundaceae. Blumea 16: 105 - 108.

Johns, R.J. 1981. The ferns and fern allies of Papua New Guinea. Part eight: the Osmundaceae. P.N.G. Univ. Tech. Res. Rep. R 48-81: 8.1 - 8.13.

Genera

1a.

Lamina thin and translucent, filmy, without stomata; sporangia scattered over the lower surface; small tree ferns with a distinct long trunk

Leptopteris (1-2)

Lamina thick, with stomata; sporangia on contracted lobes or +/- acrostichoid; caudex short and stout, not tree-like

2

2a.

Fronds +/- erect; sporangia acrostichoid, completely covering the lower surface of the uniform or only slightly contracted fertile pinnules

Todea (1)

Fronds +/- scrambling; sporangia on contracted lobes of fertile pinnae, the fertile pinnae quite different from the sterile, lacking green lamina

Osmunda (1)


Updated November 1999 by Jim Croft (jim.croft@environment.gov.au)