Austroblechnum patersonii

Blechnaceae

Austroblechnum patersonii (R.Br.) Gasper & V.A.O.Dittrich

Link to Australian Plant Name Index for publication details and synonyms: https://id.biodiversity.org.au/name/apni/8025585

Strap Water Fern

Rhizome short-creeping to erect. Sterile fronds simple or pinnatisect; fertile fronds simple, pinnatisect or pinnate. Stipe below decurrent wings of lamina 1–13 cm long, brown, stramineous to reddish brown, darkest at base; scales lanceolate to ovate, entire, dark reddish brown to bicolorous. Lamina narrowly lanceolate (simple fronds), lanceolate to ovate (dissected fronds); rachis and costae stramineous to brown or reddish brown, especially on abaxial surface, glabrous; sterile pinnae or lobes lanceolate, acuminate, 2–15 cm long, 6–32 mm wide, adnate and decurrently winged at rachis; basal pinnae with decurrent wings extending well down rachis; fertile pinnae or lobes of dissected fronds linear, to 25 cm long, 3–5 mm wide, adnate to rachis and decurrently winged. Sori covering undersurface of pinnae and wings. Spores with smooth scaberulous granulose or minutely rugulose perine; exine smooth to minutely verrucose. 

Eastern Australia and Papua New Guinea. In Australia it occurs from Cooktown NE QLD to Tas including Lord Howe Island.

Terrestrial or lithophytic on banks in wet shaded areas, usually in closed canopy rainforest. In tropical QLD usually found in montane areas.

Two subspecies are recognised:

1a. Fronds thin, papery when dry; margins undulate, crenate or serrate, not usually reflexed = subsp. patersonii

1b. Fronds firm, fleshy and brittle, coriaceous when dry; margins thin, reflexed, entire = subsp. queenslandicum

Grows well in subtropical and warm temperate areas but more difficult to grow in the lowland wet tropics.