APC Comment:When publishing the name of this species Kiesing cited the invalid Piptanthocereus uruguayanus Ritter as basionym. Under Art. 46 Note 2 and Ex. 22 Ritter's name is thus not to be included in the authority. Both Ritter and Kiesing used the spelling "uruguayanus", which was later wrongly "corrected" to "uruguayensis".