Senna rizzinii is a flowering shrub found mainly in the northeast region of Brazil. Here, we report the coding-complete genome sequence, particle morphology, mode of transmission, and the indicator host responses of an isolate of the putative allexivirus cassia mild mosaic virus (CaMMV) found in S. rizzinii. The virus was transmitted mechanically to Chenopodium amaranticolor, C. quinoa, Gomphrena globosa, which showed local lesions, and S. rizzinii, and S. occidentalis, which were infected systemically. It was also efficiently transmitted to S. rizzinii by grafting. Seed transmission was not observed. The near-complete genome sequence of the virus is 7829 nucleotides in length, containing six open reading frames (ORF), like other allexiviruses.