title: Viola kauaensis var. hosakae (Violaceae), a new variety of endemic Hawaiian violet.
abstract: The Hawaiian endemic Viola kauaensis A. Gray has a broad distribution in bogs of Kaua`i and a limited distribution on mesic ridges in the Ko`olau Mountains of O`ahu. Based on differences in scale, the O`ahu populations of Viola kauaensis had previously been described as a distinct taxon. The taxonomic status of the O`ahu populations was reevaluated through a morphometric analysis of all varieties of Viola kauaensis and the morphologically similar Viola vanroyenii. Morphological features of historic and freshly collected specimens of all varieties of Viola kauaensis were analyzed with a principal components analysis. Populations from O`ahu represent a distinct cluster that slightly overlaps with Viola kauaensis var. kauaensis. Lamina width, apex angle, and base angles contribute to the separation of the O`ahu populations from other varieties of Viola kauaensis. Due to differences in scale, the O`ahu populations are described as Viola kauaensis var. hosakae, a new critically endangered taxon.
authors.affiliation: Department of Biological Sciences, 205 Day Dorm Rd, Campbell University, Buies Creek, NC 27506, USA.
authors.forename: J Christopher
authors.initials: JC
authors.lastname: Havran
authors.affiliation: O`ahu Plant Extinction Prevention Program, 2551 Waimano Home Rd, Rm 202, Pearl City, HI 96782, USA.
authors.forename: Susan Ching
authors.initials: SC
authors.lastname: Harbin
authors.affiliation: O`ahu Plant Extinction Prevention Program, 2551 Waimano Home Rd, Rm 202, Pearl City, HI 96782, USA.
authors.forename: Talia
authors.initials: T
authors.lastname: Portner
keywords: Hawaiian Islands; O`ahu; Viola kauaensis var. hosakae; Violaceae; cleistogamy