Perrottetia wichmaniorum Lorence & W. L. Wagner, sp. nov. is described as endemic to Kaua‘i. It differs from its Hawaiian congener P. sandwicensis by its larger, thicker, more densely hirtellous-villosulous rugose leaves with a smaller length:width ratio 1.5–1.7:1], larger inflorescences with usually four degrees of branching with moderately to densely hirtellous axes, and flowers with glabrous petals. This new species falls into the Endangered (EN) category when evaluated using the IUCN Red List criteria for endangerment based on its small area of occupancy, a decline in the extent and quality of its habitat, and number of mature individuals.
