Ptisana salicina (Sm.) Murdock

Large, robust fern with fronds to 6 m long. Stipes 2 m long; lamina 1–4 m long, 2-or 3-pinnate; pinnae alternate; pinnules shortly petiolulate, narrowly lanceolate, 8–15 cm long, 1–2 cm wide, finely serrate, acute, with scattered, long cobwebby scaly hairs beneath, especially towards base and midrib. Synangia marginal, 8–10 per cm, (1–) 1.5–2.5 mm long, with (6–) 7–14 (–16) pairs of sori.

A tropical plant. It suits the warm humid tropics and subtropics. They need deep, rich, well drained soil. They need a shady and damp location. It is usually on clay soils. Adelaide Botanical Gardens. It suits hardiness zones 11-12.

As suggested by the common name Potato Fern, the fleshy, starchy rhizome has been used as a food source by some indigenous peoples. Known as Para, the fern was cultivated by Māori, and the large stipules on the rhizome were considered a delicacy (Crowe 1981). Featured as Marattia salicina on two Norfolk Island $2.00 postage stamps as part of a Norfolk Island 2008 ferns set.

Plants can be grown by planting the fattened storage organs near the base of the leaf. These growths look like ears. They need to be planted in a well lit, warm, humid position.