Zealandia is a small genus of ferns belonging to the family Polypodiaceae (order Polypodiales), subfamily Microsoroideae. The genus was established in 2019 by Testo & A.R.Field on the basis of a molecular phylogenetic study that identified three monophyletic clades within Microsoroideae as distinct from the broader genus Lecanopteris. Zealandia currently comprises four species distributed across New Zealand, eastern Australia, New Guinea, the Pacific islands, and New Caledonia.
Members of the genus are epiphytic or lithophytic ferns characterised by long, creeping grey-green rhizomes with clathrate, ovate scales. The fronds are lobed and glossy-green, leathery in texture, and range from 5 to 50 cm in length. A distinctive feature is the presence of relatively large (approximately 3–4 mm wide) circular sori on the underside of the fronds.
The best-known species, Zealandia pustulata, is widely distributed across eastern Australia and New Zealand and is commonly called the kangaroo fern or hound's tongue fern. It grows in wet sclerophyll forest, rainforest, and subalpine environments, typically in partial to full shade, and was originally described by Georg Forster as Polypodium pustulatum in 1786.
The genus remains taxonomically contested: as of 2024, Plants of the World Online treats the principal species under Lecanopteris rather than Zealandia, while the Checklist of Ferns and Lycophytes of the World and GBIF continue to recognise Zealandia as an accepted genus.
Etymology
The genus name Zealandia refers to New Zealand (Latin: Zealandia), reflecting that the type species Zealandia pustulata is native to and widespread in New Zealand. The genus was erected by Testo & A.R.Field in 2019.
Distribution
Zealandia species are distributed across the southwestern Pacific. Zealandia pustulata (the most widespread species) ranges from southeastern Queensland through New South Wales and Victoria to Tasmania, Lord Howe Island, Norfolk Island, and throughout New Zealand's North and South Islands including the Chatham, Kermadec, and Antipodes island groups. Other species extend through New Guinea, Maluku, the Bismarck Archipelago, Solomon Islands, Vanuatu, Fiji, Samoa, Pitcairn Islands, Cook Islands, Society Islands (Z. powellii), New Caledonia (Z. vieillardii), and the North Island of New Zealand (Z. novae-zealandiae).
Ecology
Zealandia pustulata grows in wet sclerophyll forest, rainforest, and more open subalpine environments. It is both epiphytic and lithophytic, colonising fallen logs, rocks, and living plants via its creeping rhizomes. The species prefers partial to full shade and is described as a middle-storey inhabitant, though it can grow from the forest floor to the canopy. Its tolerance of a range of substrates and moisture conditions makes it one of the more adaptable ferns in its range.
Taxonomy Notes
Zealandia was segregated from the subfamily Microsoroideae (Polypodiaceae) in 2019 following a molecular phylogenetic study by Testo & A.R.Field, which identified three monophyletic clades near Lecanopteris sensu stricto. The genus is closely related to Lecanopteris and two other segregate genera erected in the same study. Taxonomic acceptance is not universal: the Checklist of Ferns and Lycophytes of the World and GBIF accept Zealandia, while Plants of the World Online (as of September 2024) places the main species under Lecanopteris pustulata. The type species was originally named Polypodium pustulatum by Georg Forster (1786), transferred to Microsorum by Copeland (1947), and moved to Zealandia in 2019.
