Citrus Trees and Shrubs of the genus Melicope are found across tropical Asia and the Islands of the Pacific to Australia, New Zealand and Hawaii. They are variously known as Corkwoods, Doughwoods, Euodoias, Alani, Melicopes or Peleas. The plants are hosts to many species of Insects and other invertebrates, including many species of Butterfly and Moth Caterpillars, and Beetles and their larvae, making them an important part of the ecosystems in which they are found. However many species in Hawaii are threatened by habitat loss and competition from invasive plants.
In a paper published in the journal PhytoKeys on 25 August 2016, Kenneth Wood of the National Tropical Botanical Garden, Marc Appelhans of the Department of Systematic Botany at the University of Göttingen and the Department of Botany at the Smithsonian Institution, and Warren Wagner, also of the Department of Botany at the Smithsonian Institution, describe a new species of Melicope from Wailuku District in West Maui, Hawaii.
The new species is named Melicope oppenheimeri, in honour of Hank Oppenheimer of the Maui Nui Plant Extinction Prevention Program, who collected the first specimens of the plant. The new species is a small tree reaching 3-4 m in height, producing flowers and fruit more-or-less year round.
Melicope oppenheimeri. (A) Flowering branch, (B) Inflorescence, (C) Undehisced fruit, showing beaked carpels, (D) Fruit, partly open, (E) Fruit, fully opened (F) Fruit endocarp showing venation and hairs. Alice Tangerini in Wood et al. (2016).
Only seven trees of Melicope oppenheimeri were found, growing in the upper part of the Waihe‘e Valley at an elevation of about 770 m. Only three of these trees currently survive, and no further trees have been found, though the site where the trees were growing was accessable only by helicopter. The area is considered to be degraded by ferral Pigs, Sus scrofa, which have been introduced to the island, and which modify their environement by their foraging in ways which are highly detrimental to native Hawai'ian plants, as well as by numerous non-native plants which survive well in Pig-modified environments.
Habit of Melicope oppenheimeri. Hank Oppenheimer in Wood et al. (2016).
Due to the very low number of Melicope oppenheimeri specimens known and the disturbance to the ecosystem in which the plants were found, the species is cosidered to be Critically Endangered under the terms of the International Union for the Conservation of Nature's Red List of Threatened Species.
Melicope oppenheimeri (A) Flowers (B) Fruit, showing beaked carpels. Hank Oppenheimer in Wood et al. (2016).
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