Kuijt, J. Brittonia (1997) 49: 181. doi:10.2307/2807679
Materials are presented to the effect thatPhoradendron californicum Nutt., the nomenclatural type of the genusPhoradendron (Viscaceae), is related to southern, cataphyllous species, not to northern, acataphyllous ones. The evidence consists of the frequent occurrence of basal cataphylls in the species, variation in basal phyllotaxy, and a basically biseriate arrangement of flowers on fertile internodes. The suggestion of this southern, cataphyllous affinity is supported by the recent discovery of a strictly cataphyllous Mexican species,P. olae Kuijt, which shows median basal phyllotaxy and is in many features extremely similar toP. californicum. The nomenclatural consequences of this discovery would lead to subgen.Boreales (Trel.) Engler (and probably subgen.Aequatoriales (Trel.) Engler) being synonymized under subgen.Phoradendron, characterized by basal cataphylls (though not in all species). However, no generic subdivision of any sort is supported at this time.