Blechnum ambiguum —Water Fern—BLECHNACEAE
Habitat— Common on wet rocks, usually found in open forest, and rainforest
Distribution—North from the South Coast in New South Wales and into Queensland.
Description—A terrestrial fern
Dorrigo National Park
Fronds.—Fronds usually pendent, all similar, mostly pinnate, usually 30 to 50 cm long, pale green; pinnae becoming more coarsely toothed towards apices. Rhizome short to medium creeping, scales of the rhizome and stipe base pale brown to red–brown, much longer than broad, lanceolate to ovate. Sterile fronds with pinnae mostly 6–10 cm long, 15 to 25 mm wide, pinnae distinctly stalked, at least in the lower third of lamina, not markedly decreasing in size towards base, apices bluntly pointed; fertile fronds with pinnae usually 4 to 9 cm long, 3 to 10 mm wide and less than half as broad as the sterile pinnae.
Sori.— Forming a band on each side of the midrib covered by a continous indusium