Angiopteris is a genus of large evergreen ferns belonging to the family Marattiaceae, within the order Marattiales — one of the most ancient lineages of vascular plants. The genus is distributed throughout the paleotropics, ranging from Madagascar eastward across tropical Asia to the South Pacific islands.
Plants in this genus are notable for their imposing stature. Each bears a large, erect, woody rhizome with a broad base anchored by thick roots. The fronds are deltoid (triangular) and pinnate, reaching 5–8 metres in length, making them among the largest fronds of any fern genus. At the base of each frond sits a pair of thick, leathery stipules — in Angiopteris canaliculata these can measure up to 15 cm long and wide.
Angiopteris is unique among ferns in its spore dispersal mechanism: the spores are ejected explosively, a process thought to be driven by cavitation of an airspace between spore layers. The basal chromosome number is 2n=80. The type species is Angiopteris evecta, which has been widely introduced and has naturalized — and become invasive — in Hawaii, Jamaica, and parts of Central America, particularly in lower-elevation drainages.
Angiopteris taxonomy has a complicated history. Nearly 200 species have been described, but most are poorly defined and only a small handful are recognized in modern floras. Some smaller species with creeping rhizomes and elongate synangia have been placed in the segregate genus Archangiopteris, and a once-pinnate monotypic form was described as Macroglossum; however, molecular data supports subsuming these into a broadly circumscribed Angiopteris. The current circumscription was established by Smith et al. in 2006 on the basis of molecular phylogenetic analysis, placing the genus firmly within Marattiaceae — a family of eusporangiate ferns whose origins date to the Carboniferous period.
Distribution
Angiopteris is native to the paleotropics, extending from Madagascar through tropical Asia and Polynesia to the South Pacific islands. The type species, Angiopteris evecta, has additionally been introduced to Hawaii, Jamaica, and Central America, where it has naturalized and is considered invasive in lower-elevation stream habitats.
Ecology
Angiopteris species inhabit moist tropical forest understories. Angiopteris evecta in particular colonizes lower-elevation drainages when introduced outside its native range, forming dense stands that displace native vegetation.
Taxonomy Notes
Angiopteris was placed in Marattiaceae by Smith et al. (2006) using molecular phylogeny, within the order Marattiales. The genus has a notoriously difficult taxonomy: close to 200 names have been published, but modern treatments accept only a handful. Segregate genera Archangiopteris and Macroglossum are now included within Angiopteris on the basis of molecular data.
