Virion purification from indicator plants and partial sequencing of the replicase region of a 'sweet potato caulimo-like virus' (SPCV) isolate from Madeira, Portugal, are described. Phylogenetic analysis suggests that SPCV is a distinct member of the genus Cavemovirus (family Caulimoviridae). These results explain previous failed attempts to characterize SPCV based on antibodies or primers designed for other members of the Caulimoviridae. Using a quick DNA extraction protocol and PCR primers flanking the RT motif region, we were able to detect SPCV directly in sweet potato, thus saving considerable time during routine virus indexing. © Springer-Verlag 2010.