Euphorbia deppeana
Encyclopedia
Euphorbia deppeana is a rare species of flowering plant in the euphorb family
known by the common names Deppe's broomspurge and Oahu sandmat. It is endemic to Oahu
, Hawaii
, where it is known from only one population in moist shrublands on Nuuanu Pali. Like other native Hawaiian euphorbs it is called akoko locally.
This shrub
is erect or sprawling in form. The stems may exceed a meter in length and contain milky sap
.
The plant has never been abundant as long as the area has been surveyed for flora. It was not seen for many decades and by the 1980s it was feared extinct
. The single known population was rediscovered in 1986 and it contained fewer than 100 plants. In 1994 it was added to the United States' endangered species list
. By 2007 the population was estimated to have exceeded 100 plants, but they are hard to count because they grow on a sheer rock cliff in the middle of a tourist area.
The species is still considered endangered because there is only a single population and it is threatened by a number of processes. Several invasive plant species
have moved into the area and compete with the rare native for water, light, nutrients, and physical space. The most important non-native plants in the area include ironwood
(Casuarina equisetifolia), Hilo grass (Paspalum conjugatum), Christmasberry (Schinus terebinthifolius), and the common guava
(Psidium guajava). Other threats to the species include fires
and human interference with the plants.
Euphorbiaceae
Euphorbiaceae, the Spurge family are a large family of flowering plants with 300 genera and around 7,500 species. Most are herbs, but some, especially in the tropics, are also shrubs or trees. Some are succulent and resemble cacti....
known by the common names Deppe's broomspurge and Oahu sandmat. It is endemic to 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...
, 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 only one population in moist shrublands on Nuuanu Pali. Like other native Hawaiian euphorbs it is called akoko locally.
This shrub
Shrub
A shrub or bush is distinguished from a tree by its multiple stems and shorter height, usually under 5–6 m tall. A large number of plants may become either shrubs or trees, depending on the growing conditions they experience...
is erect or sprawling in form. The stems may exceed a meter in length and contain milky sap
Sap
Sap may refer to:* Plant sap, the fluid transported in xylem cells or phloem sieve tube elements of a plant* Sap , a village in the Dunajská Streda District of Slovakia...
.
The plant has never been abundant as long as the area has been surveyed for flora. It was not seen for many decades and by the 1980s it was feared extinct
Extinction
In biology and ecology, extinction is the end of an organism or of a group of organisms , normally a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point...
. The single known population was rediscovered in 1986 and it contained fewer than 100 plants. In 1994 it was added to the United States' endangered species list
Endangered Species Act
The Endangered Species Act of 1973 is one of the dozens of United States environmental laws passed in the 1970s. Signed into law by President Richard Nixon on December 28, 1973, it was designed to protect critically imperiled species from extinction as a "consequence of economic growth and...
. By 2007 the population was estimated to have exceeded 100 plants, but they are hard to count because they grow on a sheer rock cliff in the middle of a tourist area.
The species is still considered endangered because there is only a single population and it is threatened by a number of processes. Several invasive plant species
Invasive species
"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....
have moved into the area and compete with the rare native for water, light, nutrients, and physical space. The most important non-native plants in the area include ironwood
Casuarina equisetifolia
Casuarina equisetifolia is a she-oak species of the genus Casuarina. The native range extends from Burma and Vietnam throughout Malesia east to French Polynesia, New Caledonia, and Vanuatu, and south to Australia...
(Casuarina equisetifolia), Hilo grass (Paspalum conjugatum), Christmasberry (Schinus terebinthifolius), and the common guava
Psidium guajava
The apple guava or common guava is an evergreen shrub or small tree native to Mexico, the Caribbean, and Central and South America...
(Psidium guajava). Other threats to the species include fires
Wildfire
A wildfire is any uncontrolled fire in combustible vegetation that occurs in the countryside or a wilderness area. Other names such as brush fire, bushfire, forest fire, desert fire, grass fire, hill fire, squirrel fire, vegetation fire, veldfire, and wilkjjofire may be used to describe the same...
and human interference with the plants.