A new species of Cyanea (Campanulaceae, Lobelioideae), from the Ko'olau Mountains of O'ahu, Hawaiian Islands.

Cyaneakonahuanuiensis Sporck-Koehler, M. Waite, A.M. Williams, sp. nov., a recently documented, narrowly endemic species from the Hawaiian Island of O'ahu, is described and illustrated with photographs from the field. The closest likely relatives to the species, current conservation needs, and management future are discussed. It is currently known from 20 mature plants from two subpopulations and is restricted to a drainage below the Kōnāhua-nui summit (K1), the highest summit of the Ko'olau Mountains, located on Windward O'ahu. It differs from all other Cyanea species by its combination of densely pubescent leaves, petioles, and flowers; sparsely pubescent to glabrous stems, long calyx lobes, and staminal column being adnate to the corolla.