Nephrolepis cordifolia is a species of fern native to tropical and subtropical areas from India through Southeast Asia to Australia and the Pacific islands. It has been introduced to many other countries. It has many common names including fishbone fern, tuberous sword fern, tuber ladder fern, erect sword fern, narrow sword fern and ladder fern, and herringbone fern.
Description
Nephrolepis cordifolia is an evergreen fern that grows to between 40 and 80 centimeters, in extreme cases up to 1 meter. It forms an underground rhizome in the form of several small tubers. The pinnate fronds are erect and pinnate linear to lanceolate, glandular and simple. The rachis bears bicolored chaff scales. The petiole is covered with bicolored pale and dark brown scales.
The leaflets are entire, sessile and elongate-lanceolate. They grow up to 4.8 centimeters long and up to 0.9 cm wide. They stand at a distance of less than 1 centimeter. The sori are rounded. The spores are warty, wrinkled.
Distribution It is native to the following regions as defined in the World Geographical Scheme for Recording Plant Distributions: West-Central Tropical Africa – Cameroon, Gulf of Guinea Islands Western Indian Ocean – Comoros, Mauritius, Réunion, Seychelles China – China South-Central, China Southeast, Hainan, Tibet Eastern Asia – Japan, Kazan-retto, Korea, Nansei-shoto, Ogasawara-shoto, Taiwan Indian Subcontinent – Assam, Bangladesh, East Himalaya, India, Laccadive Islands, Nepal, Sri Lanka, West Himalaya Indo-China – Cambodia, Laos, Myanmar, South China Sea, Thailand, Vietnam Malesia – Borneo, Jawa, Lesser Sunda Islands, Malaya, Philippines, Sulawesi Australia – New South Wales, Norfolk Island, Queensland Southwestern Pacific – Fiji, New Caledonia, Vanuatu South-Central Pacific – Marquesas, Pitcairn Island, Society Islands, Tubuai Islands Northwestern Pacific – Caroline Islands North-Central Pacific – Hawaii
It has been introduced into the following regions: East Tropical Africa – Kenya, Tanzania Macaronesia – Azores, Madeira Southern Africa – Cape Provinces, KwaZulu-Natal, Northern Provinces, Swaziland Indian Subcontinent – Pakistan Indo-China – Thailand New Zealand – New Zealand North, New Zealand South Southeastern Europe – Italy Southwestern Europe – France, Spain Mexico – Mexico Central, Mexico Gulf, Mexico Southeast, Mexico Southwest Southeastern U.S.A. – Alabama, Florida, Georgia Southwestern U.S.A. – California Brazil – Brazil Northeast, Brazil South, Brazil Southeast Caribbean – Cuba, Dominican Republic, Haiti, Jamaica, Leeward Is., Puerto Rico, Windward Is. Central America – Belize, El Salvador, Guatemala, Honduras, Nicaragua, Panamá Northern South America – French Guiana, Guyana, Suriname Southern South America – Argentina Northeast, Argentina Northwest, Paraguay Western South America – Bolivia, Colombia, Ecuador, Galápagos, Peru
Habitat
They can establish themselves terrestrially, or as an epiphyte or lithophyte, provided that the location has ideal moisture and light levels. In adequate conditions, these ferns grow readily as epiphytes, typically adhering to the bark of tree branches above a water source, where they can receive round-the-clock humidity and airflow. They can be found in a multitude of environments, from deep swamps and riverbanks to rugged outcrops and rock faces, as well as roadsides, ditches, creeks, fallen trees, and even abandoned buildings and ruins. They love moist, shady locations; in their natural range, they are usually found in swamps (as an epiphyte) or along brooks and ditches of coniferous forest floodplains (growing more terrestrially).
Varieties Three varieties are recognised : Nephrolepis cordifolia var. cordifolia – western Indian Ocean (except Madagascar) to tropical and subtropical Asia, eastern Australia, and the Pacific Nephrolepis cordifolia var. pseudolauterbachii – Fiji Nephrolepis cordifolia var. pumicicola – São Tomé and southwestern Cameroon
Invasive species Nephrolepis cordifolia has become an invasive species is some areas where it has been introduced. In New Zealand it is listed on the National Pest Plant Accord, which prohibits the sale, cultivation and distribution of the plant. It is listed as an invasive species in Florida, United States.
Gallery
References
External links
Observations of this species on iNaturalist Nephrolepis cordifolia at the Global Invasive Species Database (Invasive Species Specialist Group)
Tuber ladder fern at Weedbusters (New Zealand) Nephrolepis cordifolia at the Center for Invasive Species and Ecosystem Health (United States)