| Amaranthus brownii | |
|---|---|
| |
Scientific classification 
| |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Order: | Caryophyllales |
| Family: | Amaranthaceae |
| Genus: | Amaranthus |
| Species: | †A. brownii
|
| Binomial name | |
| †Amaranthus brownii | |
Amaranthus brownii was an annual herb in the family Amaranthaceae. The plant was found only on the small island of Nihoa in the Northwestern Hawaiian Islands, growing on rocky outcrops at altitudes of 120–215 m (394–705 ft). It was one of nine species of Amaranthus in the Hawaiian Islands, as well as the only endemic Hawaiian species of the genus. It is now considered extinct.
A. brownii was first discovered during the Tanager Expedition in 1923 by botanist Edward Leonard Caum. It differed from other Hawaiian species of Amaranthus with its spineless leaf axils, linear leaves, and indehiscent fruits. It was one of 26 vascular plants on Nihoa, 17 of which are indigenous, six alien, and three endemic only to Nihoa; these latter three included A. brownii, the Nihoa fan palm or loulu, and the Nihoa carnation. A. brownii was considered the rarest plant on Nihoa and was not directly observed on the island after 1983. Past expeditions collected plant samples and seeds, but no specimens managed to survive ex situ conservation efforts outside of its native habitat. Consequently, there are no known plants or seeds from A. brownii in any botanical garden.
Conservation and recovery plans for A. brownii were proposed by the United States Fish and Wildlife Service (FWS), which administers the island of Nihoa as part of the Hawaiian Islands National Wildlife Refuge in the Papahānaumokuākea Marine National Monument. In 1996, the plant was listed by the FWS as an endangered species. In 2003, the FWS designated the island of Nihoa as a critical habitat for the plant and it was classified as critically endangered on the IUCN Red List. Following a lack of sightings for over 35 years despite intensive surveys, the species was classified as extinct on the IUCN Red List in 2018.[1]
- ^ a b Bruegmann, M.; Caraway, V.L.; Keir, M. (2018). "Amaranthus brownii". IUCN Red List of Threatened Species. 2018: e.T44077A83794603. doi:10.2305/IUCN.UK.2018-2.RLTS.T44077A83794603.en. Retrieved 19 November 2021.