In the previous commentary dedicated to Cereus lamprospermus K. Schumann, we had already noted (2010, 30-31), as Taylor also mentions (2007, 22: 10) that Cereus lamprospermus ssp. colosseus, known for its giant specimen of Mairana (Santa Cruz, Bolivia) (Ritter 1980, 2: 554) was nothing but a specimen of Cereus stenogonus K. Schumann in one of the most northwesterly areas of its distribution range. In 2011 we travelled for almost three months, around various distribution areas of C. stenogonus between Bolivia (Tarija and Santa Cruz, up to the border with Mato Grosso do Sul, BR) Paraguay (Dpts. Amambay, Concepción and Alto Paraguay) and Argentina (Misiones). We were also looking for the mysterious C. lamprospermus taxon, which is supposed to be in Paraguay, in the Dpt. Alto Paraguay, between Fuerte Olimpo and Cerro León (Schumann 1899, 166; Ritter 1979, 1: 259). We thought that a columnar cactus of this size (a tree of 6-8 meters) could not have escaped our attention. Unfortunately, we have to start this update with bad news: in 2010 the famous specimen of Mairana made well-known by Ritter and documented in N=9]Anderson (2001, 147); Hunt et al. (2006, Atlas: 134), Anceschi & Magli (2010, A&M 220, photos 01-03) was cut down by the landowners. But the surveys in the zone between Samaipata and Mairana, and more precisely between Agua Clara and Yerba Buena, revealed that the specimen formed part of a population of C. stenogonus where several individuals reach large dimensions (A&M 683, photos 27-31). Proceeding with the research, first through the Bolivian Chaco and the neighbouring Andean mountains, and then through the Paraguayan Chaco, we documented the cacti populations of arboreal or columnar growth, which are summarized in the table. The only arboreal species of the genus Cereus P. Miller, which is encountered in this part of the Chaco Biome, (and which in Paraguay should include the distribution areas of C. lamprospermus), is the dominant C. stenogonus. We also observed in the characters of some specimens of this taxon, that they have measurements that would identify them as C. lamprospermus. For example, the specimen documented in Bolivia, Tarija west of Palos Blancos (A&M 643, photos 14-19), has branches with 7 ribs (6-8 in the description of C. lamprospermus), and the areoles on the branches with 1 central spine and (9) -10 radial spines (8-11 spines in C. lamprospermus). From the collected documentation, evidence has come to light that C. lamprospermus is not a species that exists, and that as C. lamprospermus ssp. colosseus must be considered a synonym of the dominant and widespread C. stenogonus, the dimensions of which are quite variable, and whose distribution areas cross the borders with the Chaco region into the Mata Atlantica Biome region. (Quoted from: Anceschi & Magli 2013b, 41-43)