Adenophorus periens
Encyclopedia
Adenophorus periens is a rare species of fern
known by the common name pendant kihi fern. It is endemic to Hawaii
, where it is known from one population in Puna
on the island of Hawaii
and a few occurrences on Kauai
and Molokai
. The fern occurs in wet mountain forests on volcanic slopes. It grows on trees. There are perhaps 2000 individual plants remaining. This is a federally listed endangered species
of the United States.
This fern is easily distinguished from others in its genus, with its long, hanging fronds that may exceed 40 centimeters in length, twice as long as other Adenophorus. The leaflets on the fronds are twisted at an angle to the rachis
and the leaf edges are lined with unique hairs. Genetic analysis
reveals that the fern has a high genetic diversity
for such a rare species.
Threats to the species include lava
and gas
from the volcanoes on which it grows, as well as the death of its host trees, introduced species
including weed
s and feral pigs, and geothermal development
.
Fern
A fern is any one of a group of about 12,000 species of plants belonging to the botanical group known as Pteridophyta. Unlike mosses, they have xylem and phloem . They have stems, leaves, and roots like other vascular plants...
known by the common name pendant kihi fern. It is endemic to Hawaii
Hawaii
Hawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...
, where it is known from one population in Puna
Puna, Hawaii
Puna is one of the nine districts in Hawaii County, Big Island, Hawaii. The District of Puna is located on the easternmost portion of the island and shares borders to the north with the District of South Hilo and a border to the west with the District of Kaū...
on the island of Hawaii
Hawaii (island)
The Island of Hawaii, also called the Big Island or Hawaii Island , is a volcanic island in the North Pacific Ocean...
and a few occurrences on Kauai
Kauai
Kauai or Kauai, known as Tauai in the ancient Kaua'i dialect, is geologically the oldest of the main Hawaiian Islands. With an area of , it is the fourth largest of the main islands in the Hawaiian archipelago, and the 21st largest island in the United States. Known also as the "Garden Isle",...
and Molokai
Molokai
Molokai or Molokai is an island in the Hawaiian archipelago. It is 38 by 10 miles in size with a land area of , making it the fifth largest of the main Hawaiian Islands and the 27th largest island in the United States. It lies east of Oahu across the 25-mile wide Kaiwi Channel and north of...
. The fern occurs in wet mountain forests on volcanic slopes. It grows on trees. There are perhaps 2000 individual plants remaining. This is a federally listed endangered species
Endangered species
An endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters...
of the United States.
This fern is easily distinguished from others in its genus, with its long, hanging fronds that may exceed 40 centimeters in length, twice as long as other Adenophorus. The leaflets on the fronds are twisted at an angle to the rachis
Rachis
Rachis is a biological term for a main axis or "shaft".-In zoology:In vertebrates a rachis can refer to the series of articulated vertebrae, which encase the spinal cord. In this case the rachis usually form the supporting axis of the body and is then called the spine or vertebral column...
and the leaf edges are lined with unique hairs. Genetic analysis
Genetic analysis
Genetic analysis can be used generally to describe methods both used in and resulting from the sciences of genetics and molecular biology, or to applications resulting from this research....
reveals that the fern has a high genetic diversity
Genetic diversity
Genetic diversity, the level of biodiversity, refers to the total number of genetic characteristics in the genetic makeup of a species. It is distinguished from genetic variability, which describes the tendency of genetic characteristics to vary....
for such a rare species.
Threats to the species include lava
Lava
Lava refers both to molten rock expelled by a volcano during an eruption and the resulting rock after solidification and cooling. This molten rock is formed in the interior of some planets, including Earth, and some of their satellites. When first erupted from a volcanic vent, lava is a liquid at...
and gas
Volcanic gas
|250px|thumb|right|Image of the [[rhyolitic]] [[lava dome]] of [[Chaitén Volcano]] during its 2008-2010 eruption.Volcanic gases include a variety of substances given off by active volcanoes...
from the volcanoes on which it grows, as well as the death of its host trees, introduced species
Introduced species
An introduced species — or neozoon, alien, exotic, non-indigenous, or non-native species, or simply an introduction, is a species living outside its indigenous or native distributional range, and has arrived in an ecosystem or plant community by human activity, either deliberate or accidental...
including weed
Weed
A weed in a general sense is a plant that is considered by the user of the term to be a nuisance, and normally applied to unwanted plants in human-controlled settings, especially farm fields and gardens, but also lawns, parks, woods, and other areas. More specifically, the term is often used to...
s and feral pigs, and geothermal development
Geothermal electricity
Geothermal electricity is electricity generated from geothermal energy.Technologies in use include dry steam power plants, flash steam power plants and binary cycle power plants...
.