Tetramolopium stemmermanniae (Asteraceae), a New Species from Pohakuloa Training Area, Hawai'i Island

A new species endemic to Hawai'i Island, Tetramolopium stemmermanniae, is described and illustrated. Molecular and morphological evidence support T. stemmermanniae as being distinct from T.arenarium var. arenarium, T.consanguineum ssp. leptophyllum, and T.humile ssp. humile, which occur at Pohakuloa Training Area, Hawai'i Island. Tetramolopium stemmermanniae shares an upright and multibranched habit with T.arenarium var. arenarium and T.consanguineum ssp. leptophyllum but differs in the number and color of ray and disc flowers, and in having an open, paniculate inflorescence. We provide a description of the new taxon, include a key to the Tetramolopium species of Hawai'i, and a brief description of the habitat where the newly described species occurs.