A new species of Gaud. (Lobelioideae, Campanulaceae) from Maui, Hawai`i.

H. Oppenheimer, ., a new, narrowly distributed endemic species, is herein described and illustrated with line drawings and digital field photos. It is currently known from a single mature plant and is restricted to the upper Helu planeze on leeward Mauna Kahalawai, West Maui, Hawaiian Islands. It differs from all other species of Gaudich. with its narrow, shallowly lobed leaves, gently curved muricate corollas, and undulate sepals caducous in fruit. A key to the new species and its congeners on Mauna Kahalawai is provided. Its conservation status and efforts to propagate the species are discussed.