From the Greek nephros (a kidney) and lepis (a scale), in reference to the kidney-shaped indusia of the type species.

Nephrolepis exaltata (L.) Schott

Terrestrial or epiphytic ferns. Rhizome short, erect or decumbent, densely scaly, producing numerous lateral wiry stolons which initially bear tapering elongate scales with peltate bases and marginal hair-like processes. Fronds tufted, simply pinnate, often dimorphic. Stipes tufted, much shorter than lamina, not articulated to rhizome; stipe and rachis grooved on upper surface. Pinnae sessile, articulated to rachis, usually lanceolate to falcate; acroscopic margin at base often auriculate; fertile pinnae narrower; lower pinnae sterile, shorter and more widely spaced; venation open, simple or forked; hydathodes prominent on upper surface of pinnae at vein endings. Sori superficial (rarely marginal) at vein endings; indusium reniform to round, rarely linear. Spores bilateral; surface tuberculate to rugose.

A pantropical genus of c. 30 species, a few of which extend into temperate regions. Most diverse in SE Asia. The Flora of Australia publication stated six species accepted (with some reservation) in Australia. The Australian Plant Census lists nine species. Field (2020) says there are 19 species with 8 in Australia. He does not include N. multiflora that is known from Christmas Island.

Need profiles for APC names N. brownii ( Qld) and N. multiflora (Christmas Island). Neither is in FoA Vol. 48. 

Within the genus, several species groups are highly confused and exhibit considerable intergradation of characters. Identification is further complicated in immature fronds, which often have hair and scale types and other morphological features differing from those of mature fronds. Artificial hybridisation is widespread in cultivation, and probably also occurs in nature. In the absence of a world-wide revision of the genus, the delimitation of several taxa in this treatment is unsatisfactory. However, forthcoming publication of a long-delayed treatment of unknown scope (but including Australian taxa) is expected to recognise only four species in Australia (Miyamoto, pers. comm.). Some species, especially N. cordifolia , have been widely cultivated, and various cultivars or morphologically anomalous forms are popular ornamentals, partly due to ease of vegetative propagation. The tubers of N. cordifolia are said to be eaten in parts of India (J.D.Hooker, Handb. New Zealand Fl. 379, 1867) and in tropical America (C.V.Morton, Amer. Fern J. 48: 22, 1958). Needs review.

Clifford, H.T. & Constantine, J. (1980). Ferns, Fern Allies and Conifers of Australia; a Laboratory Manual 51. (University of Queensland Press: St Lucia).

Field, A.R. (2020). Classification and typification of Australian lycophytes and ferns based on Pteridophyte Phylogeny Group classification PPG I. Australian Systematic Botany 33(1): 1–102 ]77–78].

Jones, D.L. & Clemesha, S.C. (1981). Australian Ferns and Fern Allies 2nd edn, 172–176 (Reed Books: Frenchs Forest NSW).

Tindale, M.D. (1961). Davalliaceae. Contributions from the New South Wales National Herbarium, Flora Series 208: 1–14.

Wheeler, J.R. (1992). Oleandraceae, in Wheeler, J.R. (ed.) et al., Flora of the Kimberley Region, pp. 45–47. (Department of Conservation and Land Management: Como, W.A.).

Data derived from Flora of Australia Volume 48 (1998), a product of ABRS, ©Commonwealth of Australia