Polystichum aleuticum | |
---|---|
Scientific classification | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Division: | Polypodiophyta |
Class: | Polypodiopsida |
Order: | Polypodiales |
Suborder: | Polypodiineae |
Family: | Dryopteridaceae |
Genus: | Polystichum |
Species: | P. aleuticum |
Binomial name | |
Polystichum aleuticum C. Christens. | |
Polystichum aleuticum, the Aleutian holly fern [1] or Aleutian shield fern, is an endangered species of the Polystichum genus and currently consisting of a small, vulnerable population endemic found only on Adak Island, Alaska, a remote island of the Aleutian Islands chain in the northern Pacific Ocean. In 1992, 112 specimens existed in the wild, and a recovery plan was implemented. [2]
The Aleutian shield fern is the only native plant of Alaska on the federal endangered species list. As there are fewer than 150 plants known to exist, it is a very rare North American plant. [3] It was listed as endangered in 1988. [4] Polystichum aleuticum was first described in 1938, but it could not be located again until 1975 when a group was identified on Mount Reed on Adak Island. A second, third, and fourth population, all on Mount Reed, was located in 1988, 1993, and 1999, respectively. Searches on other Aleutian Islands since 1988 have failed to identify additional populations. [5] [6]
It is unlike any other known shield fern found in North America, and originally it was questioned whether it even belonged to the genus Polystichum . However, it was found to be similar to a dwarf Polystichum species native to southwestern mountains of China and the Himalayas. [7]
The Polystichum aleuticum fern is described as erect and approximately six inches tall. It usually found growing alone, rather than in groups. It has a fibrous root with dead leaf remnants attached. Its leaves, visible during the growing season, are light or dark olive green, and tapering. [8] Each of its fronds has 15 to 25 pairs of leaflets (pinnae) that are either sessile or have short stalks and are 4 to 8 mm in length. The upper leaflets each have one spore-producing sori (sometimes two) on the leaflet under surface that is protected by the indusium, a flap of tissue. The spores are produced in July and August. [7]
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(help)Adak, formerly Adak Station, is a city located on Adak Island, in the Aleutians West Census Area, Alaska, United States. At the 2020 census, the population was 171, down from 326 in 2010. It is the westernmost municipality in the United States and the southernmost city in Alaska. The city is the former location of the Adak Navy Base and Adak Naval Operating Base, NAVFAC Adak.
Sceptridium is a genus of seedless vascular plants in the family Ophioglossaceae, closely allied to the genus Botrychium. It is also closely related to the genus Botrypus. Sceptridium species are commonly called the grape-ferns.
Adak Island or Father Island is an island near the western extent of the Andreanof Islands group of the Aleutian Islands in Alaska. Alaska's southernmost town, Adak, is located on the island. The island has a land area of 274.59 square miles (711.18 km2), measuring 33.9 miles (54.5 km) long and 22 miles (35 km) wide, making it the 25th largest island in the United States.
Polystichum munitum, the western swordfern, is an evergreen perennial fern native to western North America, where it is one of the most abundant ferns in forested areas. It occurs along the Pacific coast from southeastern Alaska to southern California, and also inland east to southeastern British Columbia, northern Idaho and western Montana, with disjunctive populations in northern British Columbia, Canada; the Black Hills in South Dakota, United States; and Guadalupe Island off of Baja California, Mexico. Western swordfern is known to have locally naturalized in parts of Great Britain and Ireland.
Buldir Island is a small island in the western Aleutian Islands of the U.S. state of Alaska. It is 4.3 miles (6.9 km) long and 2.5 miles (4.0 km) wide with an area of 7.4482 square miles (19.291 km2). Buldir is farther from the nearest land than any other Aleutian Island. Its nearest neighbors are Kiska in the Rat Island group, 68 miles (109 km) to the east, and Shemya in the Near Island group, 64 miles (103 km) to the west. Buldir Island is uninhabited. It is part of the Alaska Maritime National Wildlife Refuge. It has been designated a Research Natural Area.
Polystichum is a genus of ferns in the family Dryopteridaceae, subfamily Dryopteridoideae, according to the Pteridophyte Phylogeny Group classification of 2016. The genus has about 500 species and has a cosmopolitan distribution. The highest diversity is in eastern Asia, with about 208 species in China alone; the region from Mexico to Brazil has at least 100 additional species; Africa, North America, and Europe have much lower diversity. Polystichum species are terrestrial or rock-dwelling ferns of warm-temperate and montane-tropical regions. They are often found in disturbed habitats such as road cuts, talus slopes, and stream banks.
Adiantum aleuticum, the western maidenhair fern or Aleutian maidenhair, is a species of deciduous fern in the genus Adiantum.
Dryopteris marginalis, vernacularly known as the marginal shield fern or marginal wood fern, is a perennial species of fern found in damp shady areas throughout eastern North America, from Texas to Minnesota and Newfoundland. It favors moderately acid to circumneutral soils in cooler areas but is fairly drought-resistant once established. In the warmer parts of its range, it is most likely to be found on north-facing non-calcareous rock faces. It is common in many altitudes throughout its range, from high ledges to rocky slopes and stream banks. Marginal wood fern's name derives from the fact that the sori are located on the margins, or edges of the leaflets.
Polystichum acrostichoides, commonly denominated Christmas fern, is a perennial, evergreen fern native to eastern North America, from Nova Scotia west to Minnesota and south to Florida and eastern Texas. It is one of the most common ferns in eastern North America, being found in moist and shady habitats in woodlands, stream banks and rocky slopes. The common name derives from the evergreen fronds, which are often still green at Christmas.
Kasatochi Island, also known as Kasatochi volcano, is an active stratovolcano and part of the Andreanof Islands subgroup of the Aleutian Islands of southwestern Alaska. On 7 August 2008, Kasatochi began erupting explosively with an ash plume reaching 45,000 feet. The eruption lasted for 24 hours and destroyed most life on the island. It currently does not support any consistent human population.
Woodsia ilvensis, commonly known as oblong woodsia, is a fern found in North America and northern Eurasia. Also known as rusty woodsia or rusty cliff fern, it is typically found on sunny, exposed cliffs and rocky slopes and on thin, dry, acidic soils.
The Aleutian Islands, also called the Aleut Islands or Aleutic Islands and known before 1867 as the Catherine Archipelago, are a chain of 14 large volcanic islands and 55 smaller islands. Most of the Aleutian Islands belong to the U.S. state of Alaska, but some belong to the Russian federal subject of Kamchatka Krai. They form part of the Aleutian Arc in the Northern Pacific Ocean, occupying a land area of 6,821 sq mi (17,666 km2) and extending about 1,200 mi (1,900 km) westward from the Alaska Peninsula toward the Kamchatka Peninsula in Russia, and act as a border between the Bering Sea to the north and the Pacific Ocean to the south. Crossing longitude 180°, at which point east and west longitude end, the archipelago contains both the westernmost part of the United States by longitude and the easternmost by longitude. The westernmost U.S. island in real terms, however, is Attu Island, west of which runs the International Date Line. While nearly all the archipelago is part of Alaska and is usually considered as being in the "Alaskan Bush", at the extreme western end, the small, geologically related Commander Islands belong to Russia.
Polystichum imbricans is a species of fern known by the common names narrowleaf swordfern and imbricate sword fern. It is native to western North America from British Columbia to southern California, where it grows in rocky habitat in coastal and inland mountain ranges and foothills. This fern produces several erect linear or lance-shaped leaves up to 80 centimeters long. Each leaf is made up of many narrow, overlapping, sometimes twisting leaflets each 2 to 4 centimeters long. The leaflets have toothed edges. This fern readily forms hybrids, some of which are fertile and are considered separate species, such as Polystichum californicum, its hybrid with P. dudleyi.
Polystichum lonchitis is a species of fern known by the common name northern hollyfern, or simply holly-fern. It is native to much of the Northern Hemisphere from Eurasia to Alaska to Greenland and south into mountainous central North America. It has stiff, glossy green, erect fronds and grows in moist, shady, rocky mountain habitats.
Polystichum scopulinum is a species of fern known by the common names mountain hollyfern and rock sword fern. It is native to much of western North America, and it is known from disjunct occurrences in eastern Canada as well. It grows in rocky habitat, often in full sun. It is widespread but mostly found in small populations, and is noted to be most abundant on serpentine soils. This fern produces several erect, narrowly lance-shaped leaves up to 50 centimeters in length. The leaves narrow near the bases. Each leaf is divided into many lance-shaped or oblong leaflets up to 3 centimeters long. The toothed leaflets are sometimes twisted on their axes and overlapping.
Polystichum proliferum, commonly known as mother shield fern is an Australian endemic fern. The genus name Polystichum is derived from Greek poly - many, and stichos - rows referring to the many rows of sori. The species name is derived from Latin, Proli – offspring and fer - bearing referring to the proliferous buds, a prominent feature of the species.
Polystichum vestitum, commonly known as the prickly shield fern or pūnui (Maori), is a hardy, evergreen or semi-evergreen ground fern.
Diplazium molokaiense is a rare species of fern known by the common name Molokai twinsorus fern. It is endemic to Hawaii, where it is one of the rarest ferns. It has historically been found on the islands of Kauai, Oahu, Lanai, Molokai, and Maui, but it is thought to have been extirpated from four of them and today can be found only on Maui where fewer than 70 individual plants remain. The fern was federally listed as an endangered species of the United States in 1994.
Adiantum viridimontanum, commonly known as Green Mountain maidenhair fern, is a fern found only in outcrops of serpentine rock in New England and Eastern Canada. The leaf blade is cut into finger-like segments, themselves once-divided, which are borne on the outer side of a curved, dark, glossy rachis. These finger-like segments are not individual leaves, but parts of a single compound leaf. The "fingers" may be drooping or erect, depending on whether the individual fern grows in shade or sunlight. Spores are borne under false indusia at the edge of the subdivisions of the leaf, a characteristic unique to the genus Adiantum.
Wilfred "Wilf" Borden Schofield was a Canadian botanist, specializing in mosses and liverworts. He was considered by many "the foremost bryologist in Canada".