Gleichenia is a genus of ferns in the family Gleicheniaceae, order Gleicheniales, class Polypodiopsida. The family as a whole comprises about eight genera and roughly 160 species and represents one of the oldest and most widespread living lineages of ferns, with fossil relatives dating to the Triassic.
Plants in this genus are characterised by creeping rhizomes from which arise compound fronds that fork repeatedly — a form of pseudodichotomous branching — with the final segments arranged in a pinnate pattern. The sori (spore-bearing clusters) are borne on the underside of the fronds, each consisting of a few exposed sporangia with no protective indusium covering them. A particularly distinctive feature is that the sori are housed in small chambers, or pits, sunk into the lamina — a trait reported only for Gleichenia among ferns.
The genus is most closely related to Stromatopteris, a monotypic genus restricted to New Caledonia. Within Gleicheniaceae, other related genera include Dicranopteris, Sticherus, and Diplopterygium, which together cover a pantropical to warm-temperate distribution. Species found in the genus or formerly placed here — such as Gleichenia microphylla (wire fern), Gleichenia dicarpa (pouched coral fern), Gleichenia alpina (alpine coral fern), and Gleichenia polypodioides — are native primarily to Australia, New Zealand, South Africa, and adjacent southern-hemisphere regions. They frequently colonise open, disturbed, or nutrient-poor habitats including heathlands, bogs, cliff faces, and subalpine zones.
Etymology
The genus name Gleichenia honours the German botanist Friedrich Wilhelm von Gleichen-Russwurm (1717–1783), an early microscopist and naturalist. The name was applied by the British botanist Robert Brown in his 1810 work Prodromus Florae Novae Hollandiae et Insulae Van Diemen.
Distribution
Species in or formerly attributed to Gleichenia occur predominantly in the Southern Hemisphere, with strongholds in Australia, New Zealand, sub-Saharan Africa (particularly South Africa), and South America. They typically grow in open, well-lit, and nutrient-poor habitats such as heathlands, fynbos, montane grasslands, and subalpine scrub, often forming dense, impenetrable thickets in disturbed or fire-prone landscapes.
Taxonomy Notes
Gleichenia sensu stricto is a small, residual genus after a series of segregations. Many species formerly placed in Gleichenia have been moved to related genera: Dicranopteris, Sticherus, Diplopterygium, and Hicriopteris. The family Gleicheniaceae (order Gleicheniales) now encompasses eight genera and about 160 species total; the formerly separate families Dicranopteridaceae and Stromatopteridaceae have been subsumed into it. GBIF backbone versions disagree on the number of accepted species in the genus, reflecting ongoing taxonomic revision.
