Transfer of Four New Guinean Rhus Species to Toxicodendron (Anacardiaceae)

Four New Guinean species currently recognized in the genus Rhus L. (Anacardiaceae), R. caudata Lauterb., R. lamprocarpa Merr. & L. M. Perry, R. lenticellosa Lauterb., and R. linguata Slis, are transferred to Toxicodendron Mill. based on morphological and molecular data. All share the characteristic fruit of the poison ivy genus, clearly distinguishable by an exocarp separating from a white mesocarp that is striated with black resin canals. The inclusion of these species expands the known distribution of Toxicodendron eastward to New Guinea. The new combinations T. lamprocarpum (Merr. & L. M. Perry) J. D. Mitch., Pell & J. Wen, T. lenticellosum (Lauterb.) J. D. Mitch., Pell & J. Wen, and T. linguatum (Slis) J. D. Mitch., Pell & J. Wen are published. Toxicodendron dalyanum J. D. Mitch., Pell & J. Wen is published as a replacement name for R. caudata. A neotype is designated for R. caudata, and a lectotype for R. lenticellosum.