Cyperus pennatiformis
Encyclopedia
Cyperus pennatiformis is a rare species of sedge
known by the common name coastal flatsedge. It is endemic to Hawaii
, where it grows on the islands of Maui
, Kauai
, and Laysan
. It is a federally listed endangered species
of the United States.
This sedge grows 40 centimeters to 1.2 meters tall with leathery leaves as long as the stem or longer. The flower cluster atop the stem is umbrella
-shaped and up to 15 centimeters long by 25 wide. It contains up to 18 spikes which are each made up of several yellowish or grayish spikelets. The spikelet contains up to 25 flowers.
Today this plant grows on Maui
, Kauai
, and Laysan
; it has recently been extirpated
from Oahu
and the island of Hawaii
. The most recent surveys found about 30 individual plants on Maui and four populations on Kauai; these represent the subspecies pennatiformis. On Laysan the plants are of subspecies bryanii, known as Laysan sedge or Bryan's sedge. In 2008 a total of 488 individuals were counted. The Laysan sedge, though rare, appears to be reproducing successfully.
On Maui the sedge grows on seaside cliffs where it is washed with ocean spray. The habitat is a type of coastal forest dominated by hala
(Pandanus tectorius). On Kauai it can be found in moist forested canyons. On Laysan ssp. bryanii grows in wetland
s and sand dunes
.
This plant is threatened by a number of processes, chiefly habitat destruction and degradation by feral
ungulate
s such as pigs and goats
and the presence of non-native plants
. The worst invasive plants include shoebutton
(Ardisia elliptica), lantana
(Lantana camara), yellow foxtail (Setaria parviflora), and Pride of India
(Melia azedarach). On Laysan this sedge and other plants were decimated by introduced rabbits. The seeds are eaten by the Laysan Finch
(Telespiza cantans).
Cyperaceae
Cyperaceae are a family of monocotyledonous graminoid flowering plants known as sedges, which superficially resemble grasses or rushes. The family is large, with some 5,500 species described in about 109 genera. These species are widely distributed, with the centers of diversity for the group...
known by the common name coastal flatsedge. 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 grows on the islands of Maui
Maui
The island of Maui is the second-largest of the Hawaiian Islands at and is the 17th largest island in the United States. Maui is part of the state of Hawaii and is the largest of Maui County's four islands, bigger than Lānai, Kahoolawe, and Molokai. In 2010, Maui had a population of 144,444,...
, 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 Laysan
Laysan
Laysan , located northwest of Honolulu at N25° 42' 14" W171° 44' 04", is one of the Northwestern Hawaiian Islands. It comprises one land mass of , about 1 by 1.5 miles in size . It is an atoll of sorts, although the land completely surrounds a shallow central lake some above sea level that has...
. It 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 sedge grows 40 centimeters to 1.2 meters tall with leathery leaves as long as the stem or longer. The flower cluster atop the stem is umbrella
Umbrella
An umbrella or parasol is a canopy designed to protect against rain or sunlight. The term parasol usually refers to an item designed to protect from the sun; umbrella refers to a device more suited to protect from rain...
-shaped and up to 15 centimeters long by 25 wide. It contains up to 18 spikes which are each made up of several yellowish or grayish spikelets. The spikelet contains up to 25 flowers.
Today this plant grows on Maui
Maui
The island of Maui is the second-largest of the Hawaiian Islands at and is the 17th largest island in the United States. Maui is part of the state of Hawaii and is the largest of Maui County's four islands, bigger than Lānai, Kahoolawe, and Molokai. In 2010, Maui had a population of 144,444,...
, 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 Laysan
Laysan
Laysan , located northwest of Honolulu at N25° 42' 14" W171° 44' 04", is one of the Northwestern Hawaiian Islands. It comprises one land mass of , about 1 by 1.5 miles in size . It is an atoll of sorts, although the land completely surrounds a shallow central lake some above sea level that has...
; it has recently been extirpated
Local extinction
Local extinction, also known as extirpation, is the condition of a species which ceases to exist in the chosen geographic area of study, though it still exists elsewhere...
from Oahu
Oahu
Oahu or Oahu , known as "The Gathering Place", is the third largest of the Hawaiian Islands and most populous of the islands in the U.S. state of Hawaii. The state capital Honolulu is located on the southeast coast...
and 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...
. The most recent surveys found about 30 individual plants on Maui and four populations on Kauai; these represent the subspecies pennatiformis. On Laysan the plants are of subspecies bryanii, known as Laysan sedge or Bryan's sedge. In 2008 a total of 488 individuals were counted. The Laysan sedge, though rare, appears to be reproducing successfully.
On Maui the sedge grows on seaside cliffs where it is washed with ocean spray. The habitat is a type of coastal forest dominated by hala
Pandanus tectorius
Pandanus tectorius is a species of Pandanus that is native to Malesia, eastern Australia, and the Pacific Islands. Common names include Thatch Screwpine, Hala , Bacua , and Vacquois ....
(Pandanus tectorius). On Kauai it can be found in moist forested canyons. On Laysan ssp. bryanii grows in wetland
Wetland
A wetland is an area of land whose soil is saturated with water either permanently or seasonally. Wetlands are categorised by their characteristic vegetation, which is adapted to these unique soil conditions....
s and sand dunes
Dune
In physical geography, a dune is a hill of sand built by wind. Dunes occur in different forms and sizes, formed by interaction with the wind. Most kinds of dunes are longer on the windward side where the sand is pushed up the dune and have a shorter "slip face" in the lee of the wind...
.
This plant is threatened by a number of processes, chiefly habitat destruction and degradation by feral
Feral
A feral organism is one that has changed from being domesticated to being wild or untamed. In the case of plants it is a movement from cultivated to uncultivated or controlled to volunteer. The introduction of feral animals or plants to their non-native regions, like any introduced species, may...
ungulate
Ungulate
Ungulates are several groups of mammals, most of which use the tips of their toes, usually hoofed, to sustain their whole body weight while moving. They make up several orders of mammals, of which six to eight survive...
s such as pigs and goats
Feral goat
The feral goat is the domestic goat when it has become established in the wild. Feral goats occur in Australia, New Zealand, Ireland, Great Britain, Hawaii, the Galapagos and in many other parts of the world...
and the presence of non-native plants
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...
. The worst invasive plants include shoebutton
Ardisia elliptica
Ardisia elliptica is an evergreen tree, also known as the shoebutton, native to the west coast of India, Sri Lanka, Indochina, Malaysia, Indonesia and New Guinea. It a prolific reproducer which has made it a successful invasive species in other locations.A. elliptica is a tropical understory shrub...
(Ardisia elliptica), lantana
Lantana camara
Lantana camara, also known as Spanish Flag or West Indian Lantana, is a species of flowering plant in the verbena family, Verbenaceae, that is native to the American tropics. It has been introduced into other parts of the world as an ornamental plant and is considered an invasive species in many...
(Lantana camara), yellow foxtail (Setaria parviflora), and Pride of India
Melia azedarach
Melia azedarach is a species of deciduous tree in the mahogany family, Meliaceae, that is native to Pakistan, India, Indochina Southeast Asia and Australia...
(Melia azedarach). On Laysan this sedge and other plants were decimated by introduced rabbits. The seeds are eaten by the Laysan Finch
Laysan Finch
The Laysan Finch is a species of finch in the Hawaiian honeycreeper subfamily, Drepanidinae, that is endemic to the Northwestern Hawaiian Islands. It is one of four remaining finch-billed Hawaiian honeycreepers, and is closely related to the smaller Nihoa Finch. The Laysan Finch is named for...
(Telespiza cantans).