The taxonomic status of Vaccinium pallidum, the hillside blueberries including Vaccinium vacillans

Three hundred and seventy three specimens of Vaccinium § Cyanococcus were collected from 43 sites in eastern North America for taxonomic studies. Data collected using various techniques indicate that the hillside blueberries should be recognized as a single species for which the name Vaccinium pallidum Aiton has nomenclatural priority. Three characters, viz. plant height, leaf width and shape, and leaf margin, separate V. pallidum from V. angustifolium; plant height, growth habit, and leaf width separate V. pallidum from V. corymbosum; while leaf size and shape, glandular indumentum, and calyx pubescence separate V. tenellum from V. pallidum. Although V. pallidum and V. corymbosum are sympatric, only a few natural hybrids have been found among the collected material. Crossing trials among the species yielded experimental phenological data which corroborated the validity of these morphological groups.