Angiopteris

Angiopteris is a genus of huge evergreen ferns from the Marattiaceae family, found throughout the paleotropics from Madagascar to the South Pacific islands. Species of smaller stature with elongate synangia and creeping rhizomes are sometimes segregated into the genus Archangiopteris, and a once-pinnate monotypic segregate genus has been called Macroglossum, but molecular data supports inclusion of these taxa within a broad concept of Angiopteris. Angiopteris evecta has been introduced and naturalized in Hawaii, Jamaica, and parts of Central America, where it has become an invasive weed in lower elevation drainages. They feature a large, erect, woody rhizome with a wide base supported by thick roots. The fronds are deltoid, pinnate, 5–8 metres (16–26 ft) long, with spreading leaflets. Angiopteris is unique among ferns in having explosively dispersed spores, thought to be caused by the cavitation of an airspace between spore layers. The basal chromosome number for this genus is 2n=80. The type species is Angiopteris evecta. Angiopteris taxonomy is poorly understood, with nearly 200 poorly defined named species, only a small handful of which are recognized in modern floras.