Thylacopteris diaphana (Brause) Copel.

Rhizome 2-3 mm thick, internodes 3-12 cm long, vascular strands without sclerenchymatous sheaths, sclerenchyma strands absent. Rhizome scales 2.3-4.4 mm. Stipe to 13 cm, lamina to 45 by 6.5 cm, 4-5 as long as the stipe, pinnae 5-7 mm wide, crenate to serrate, obtuse to acute. Veins free, simple or once forked, very rarely uniting to form an empty areole. Sori superficial, 1-1.8 mm diam. Sporangia on stalks c. 0.4 mm long. Spores 58-64 µm, slightly pusticulate with a reticulate perispore.