Hillebrandia
Encyclopedia
Hillebrandia sandwicensis is a species of a herbaceous perennial
flowering plant
native to some of the Hawaiian Islands
. Common names include aka aka awa and pua maka nui. The genus name honors the German physician William Hillebrand
.
In terms of morphology, H. sandwicensis similar to Begonia, but differences in flower structure, pollen morphology, and fruit differentiate the two genera. It produces tubers, to which above–ground parts of the plant die back to
after producing fruit in the summer. The seeds are very small. Plants regrow in January. It blooms from February to June. It is monoecious
, with succulent
branches. It is found in humid ravines covered with forest at altitudes of 900–1800 meters. Additionally, H. sandwicensis is the only member of its family
natively found in the Hawaiian Islands.
It is classified in the family Begoniaceae and is the only species in the genus Hillebrandia; indeed, it the only one of the 1400 or so species in the family Begoniaceae not to be a member of the genus Begonia
. It is the sister taxon to the rest of its family. The time of the split is considerably older than the oldest above–water Hawaiian Island (Kure Atoll
) by an appreciable period of time. This arises a bit of a mystery as to how a monotypic genus got to a remote island chain considerably younger than itself. It has been proposed that, even though forested ravines are not particularly windy, Hillebrandia island–hopped
down the Hawaiian – Emperor seamount chain (then islands) via the wind often enough to colonize each island in turn, a process aided by a Cenozoic
climate allowing it to live at lower altitudes than today, regardless of where the genus originated from. Hillebrandia may also be younger than previous estimates.
H. sandwicensis is currently found only on the islands of Maui
, Molokai
, and Kauai
. It is locally extinct
on Oahu
, and does not occur on the Big Island. Despite an abundance of suitable habitat, the species is localized and uncommon. It has recently been getting rarer, but despite this, it is not (as of 2011) listed on the International Union for the Conservation of Nature's Red List
. However, a 1999 document from the American Fish and Wildlife Service did list H. sandwicensis as one of 202 "Other Species of Concern".
Perennial plant
A perennial plant or simply perennial is a plant that lives for more than two years. The term is often used to differentiate a plant from shorter lived annuals and biennials. The term is sometimes misused by commercial gardeners or horticulturalists to describe only herbaceous perennials...
flowering plant
Flowering plant
The flowering plants , also known as Angiospermae or Magnoliophyta, are the most diverse group of land plants. Angiosperms are seed-producing plants like the gymnosperms and can be distinguished from the gymnosperms by a series of synapomorphies...
native to some of the Hawaiian Islands
Hawaiian Islands
The Hawaiian Islands are an archipelago of eight major islands, several atolls, numerous smaller islets, and undersea seamounts in the North Pacific Ocean, extending some 1,500 miles from the island of Hawaii in the south to northernmost Kure Atoll...
. Common names include aka aka awa and pua maka nui. The genus name honors the German physician William Hillebrand
William Hillebrand
William Hillebrand was a German physician. He traveled the world, including over 20 years in the Hawaiian islands. In 1850, Hillebrand lived at what is now Foster Botanical Garden in Honolulu. He also became known as a botanist.-Life and career:...
.
In terms of morphology, H. sandwicensis similar to Begonia, but differences in flower structure, pollen morphology, and fruit differentiate the two genera. It produces tubers, to which above–ground parts of the plant die back to
Dormancy
Dormancy is a period in an organism's life cycle when growth, development, and physical activity are temporarily stopped. This minimizes metabolic activity and therefore helps an organism to conserve energy. Dormancy tends to be closely associated with environmental conditions...
after producing fruit in the summer. The seeds are very small. Plants regrow in January. It blooms from February to June. It is monoecious
Plant sexuality
Plant sexuality covers the wide variety of sexual reproduction systems found across the plant kingdom. This article describes morphological aspects of sexual reproduction of plants....
, with succulent
Succulent plant
Succulent plants, also known as succulents or fat plants, are water-retaining plants adapted to arid climates or soil conditions. Succulent plants store water in their leaves, stems, and also in roots...
branches. It is found in humid ravines covered with forest at altitudes of 900–1800 meters. Additionally, H. sandwicensis is the only member of its family
Begoniaceae
Begoniaceae is a family of flowering plants with about 1400 species occurring in the subtropics and tropics of both the New World and Old World. All but one of the species are in the genus Begonia. The only other genus in the family, Hillebrandia, is endemic to the Hawaiian Islands and has a single...
natively found in the Hawaiian Islands.
It is classified in the family Begoniaceae and is the only species in the genus Hillebrandia; indeed, it the only one of the 1400 or so species in the family Begoniaceae not to be a member of the genus Begonia
Begonia
Begonia is a genus in the flowering plant family Begoniaceae and is a perennial. The only other members of the family Begoniaceae are Hillebrandia, a genus with a single species in the Hawaiian Islands, and the genus Symbegonia which more recently was included in Begonia...
. It is the sister taxon to the rest of its family. The time of the split is considerably older than the oldest above–water Hawaiian Island (Kure Atoll
Kure Atoll
Kure Atoll or Ocean Island is an atoll in the Pacific Ocean beyond Midway Atoll in the Northwestern Hawaiian Islands at . The only land of significant size is called Green Island and is habitat for hundreds of thousands of seabirds...
) by an appreciable period of time. This arises a bit of a mystery as to how a monotypic genus got to a remote island chain considerably younger than itself. It has been proposed that, even though forested ravines are not particularly windy, Hillebrandia island–hopped
Island hopping
Island hopping is a term that refers to the means of crossing an ocean by a series of shorter journeys between islands, as opposed to a single journey directly across the ocean to the destination.- Forms :...
down the Hawaiian – Emperor seamount chain (then islands) via the wind often enough to colonize each island in turn, a process aided by a Cenozoic
Cenozoic
The Cenozoic era is the current and most recent of the three Phanerozoic geological eras and covers the period from 65.5 mya to the present. The era began in the wake of the Cretaceous–Tertiary extinction event at the end of the Cretaceous that saw the demise of the last non-avian dinosaurs and...
climate allowing it to live at lower altitudes than today, regardless of where the genus originated from. Hillebrandia may also be younger than previous estimates.
H. sandwicensis is currently found only 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,...
, 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...
, and 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",...
. It is locally extinct
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...
on 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 does not occur on the Big Island. Despite an abundance of suitable habitat, the species is localized and uncommon. It has recently been getting rarer, but despite this, it is not (as of 2011) listed on the International Union for the Conservation of Nature's Red List
IUCN Red List
The IUCN Red List of Threatened Species , founded in 1963, is the world's most comprehensive inventory of the global conservation status of biological species. The International Union for Conservation of Nature is the world's main authority on the conservation status of species...
. However, a 1999 document from the American Fish and Wildlife Service did list H. sandwicensis as one of 202 "Other Species of Concern".
External links
- Hillebrandia sandwicensis. The Nature Conservancy.