T.E.R:R.A.I.N - Taranaki Educational Resource: Research, Analysis and Information Network

Nephrolepis cordifolia (Ladder fern)

Kingdom: Plantae
Division: Pteridophyta
Class: Pterophyta
Order: Polypodiales 
Family: Lomariopsidaceae
Genus: Nephrolepis
Species: Nephrolepis cordifolia
Common name: Ladder fern, Erect sword fern, Tuber ladder fern, Chinese ladder fern, tuber sword fern, Boston fern, Fishbone Fern

Nephrolepis cordifolia national classification: National Pest Plant Accord – banned from being sold, propagated or distributed. There is a similar native ladder fern, but it has no tubers and is rare. It is found only in geothermal sites and on Raoul Island.
It is a terrestrial or epiphytic fern that grows to one metre in height, with rhizomes and producing many long runners. Tuber ladder ferns have round, 1-3cm hairy potato-like tubers. This is the only fern with tubers. Leaves: fronds are 40-100 x 5-8cm erect and arching when long with serrated leaflets Tuber ladder ferns spread by spores, runners and tubers. Dense, long-lived patches are formed, often spreading to cover large areas. It grows in damp or dry, on ground or trees, in the open or shady spots. It can grow in most soil types, and in hot to mid-cool temperatures. It invades disturbed bush and shrubland, fernalnd, tussock land, coastal forest and streamsides by crowding out groundcovers, shrubs and other ferns. It can contribute to streamside erosion. Runners and tubers quickly spread from dumped vegetation and soil, occasionally through flooding. Runners and tubers will both resprout if not disposed of carefully.

The topside of fertile frond

The underside of a fertile frond

The top surface of a sterile frond.

The underside of a sterile frond.
New growing fronds
Growing tips of fronds

The 1-3cm hairy potato-like tubers

Thanks to Wikipedia for text and information: https://creativecommons.org/licenses/by-sa/3.0/