 It is one of 26 vascular plants on Nihoa , 17 of which are indigenous , six alien , and three endemic only to Nihoa , including A. brownii , the Nihoa fan palm or loulu , and the Nihoa carnation . A. brownii is considered the rarest plant on Nihoa and has not been directly observed on the island since 1983 . Past expeditions collected plant samples and seeds , but no specimens have managed to survive ex @-@ situ conservation efforts outside of its native habitat . There are no known plants or seeds from A. brownii in any botanical gardens . 
