''Argyroxiphium sandwicense'', the Hawaiʻi silversword, or ''hinahina'' is a species of
silversword. It is
endemic
Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...
to
Hawaii
Hawaii ( ; ) is an island U.S. state, state of the United States, in the Pacific Ocean about southwest of the U.S. mainland. One of the two Non-contiguous United States, non-contiguous U.S. states (along with Alaska), it is the only sta ...
. The two subspecies are separated by geography. Both subspecies are rare, threatened and federally protected.
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Haleakala silversword
''Argyroxiphium sandwicense'' subsp. ''macrocephalum'', the east Maui silversword or Haleakalā silversword, is a rare plant, part of the family Asteraceae. The silversword in general is referred to as ''āhinahina'' in Hawaiian (literally, "ve ...
(''A. sandwicense'' subsp. ''macrocephalum'') is found on the mountain
Haleakalā
Haleakalā (; Hawaiian: ), or the East Maui Volcano, is a massive, active shield volcano that forms more than 75% of the Hawaiian Islands, Hawaiian Island of Maui. The western 25% of the island is formed by another volcano, Mauna Kahalawai, als ...
on the island of
Maui
Maui (; Hawaiian language, Hawaiian: ) is the second largest island in the Hawaiian archipelago, at 727.2 square miles (1,883 km2). It is the List of islands of the United States by area, 17th-largest in the United States. Maui is one of ...
at elevations above . It is a federally listed
threatened species
A threatened species is any species (including animals, plants and fungi) which is vulnerable to extinction in the near future. Species that are threatened are sometimes characterised by the population dynamics measure of ''critical depensatio ...
.
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Mauna Kea silversword (''A. sandwicense'' subsp. ''sandwicense'') is found on the mountain
Mauna Kea
Mauna Kea (, ; abbreviation for ''Mauna a Wākea''); is a dormant Shield volcano, shield volcano on the Hawaii (island), island of Hawaii. Its peak is above sea level, making it the List of U.S. states by elevation, highest point in Hawaii a ...
on the
Hawaii Island
Hawaii is the largest island in the United States, located in the state of Hawaii, the southernmost state in the union. It is the southeasternmost of the Hawaiian Islands, a chain of volcanic islands in the North Pacific Ocean. With an area of ...
at elevations above . It is a federally listed
endangered species
An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching, inv ...
. As few as 40 individuals are left.
Reproduction
The silversword flowers only once in its lifespan of 20 to 90 years.
Natural history
One of the reasons that the silversword is now an endangered species is the introduction of foreign hoofed mammals (
ungulate
Ungulates ( ) are members of the diverse clade Euungulata ("true ungulates"), which primarily consists of large mammals with Hoof, hooves. Once part of the clade "Ungulata" along with the clade Paenungulata, "Ungulata" has since been determined ...
s) by European colonizers. As the population of ungulates (most notably sheep) grew, the population of silversword decreased (Robichaux, 1997).
Threats
One study found that it may not survive
climate change
Present-day climate change includes both global warming—the ongoing increase in Global surface temperature, global average temperature—and its wider effects on Earth's climate system. Climate variability and change, Climate change in ...
.
References
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External links
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{{Authority control
sandwicense
Endemic flora of Hawaii