Charles (2009, 116-121) divided Gymnocalycium schroederianum Osten into three subspecies, recognizing in addition to ssp. schroederianum, the following; Gymnocalycium schroederianum ssp. bayense R. Kiesling and Gymnocalycium schroederianum ssp. boessii R. Kiesling, E. Marchesi & O. Ferrari, respectively found south and north of the area of the type populations. Overall, the populations that constitute G. schroederianum are located between Argentina (Buenos Aires, Corrientes, Entre Ríos, Santa Fe), Brazil (Rio Grande do Sul), and Uruguay (Rio Negro). Based on our studies in the habitats of Cerro Curacá (A&M 956) and of the Sierras Bayas (A&M 961 and A&M 963), Olavarria, Buenos Aires Province, Argentina, in 2014, and in agreement with Hunt et al. (2006, text: 134), we believe that G. schroederianum ssp. bayense should be considered a synonym of G. schroederianum since, as also already highlighted by Charles (2009, 119), the only difference with the type populations is the geographical disjunction (i.e. about 500 km south for the ssp. bayense). Moreover, as already noted in the case of Gymnocalycium pflanzii (Vaupel) Werdermann (Anceschi & Magli 2013a, 58), the reason why the spatial continuity, which usually exists between the various populations that constitute a natural species is broken, may be different (i.e. populations that are not yet recognized, or more likely, that are extinct). Concerning Papsch's proposal (2001), to neotypify the name Echinocactus hyptiacanthus with a plant of this taxon from the Sierras Bayas, we agree with Charles (ibidem, 119), on the fact that there is already a neotypification by Kiesling of the same name, applied to one of the members of the group of Gymnocalycium uruguayense (Arechavaleta) Britton & Rose, and therefore consider Papsch's proposal superfluous. In our system, according to Hunt et al. (2006, text: 129, 131), we consider Gymnocalycium hyptiacanthum (Lemaire) Britton & Rose and Gymnocalycium netrelianum (Monville) Britton & Rose to be of controversial application, while for further information on the group of taxa relating to G. uruguayense, we refer to the comment in our penultimate booklet (Anceschi & Magli 2013a, 67-70). It is interesting to note how Papsch (2015 (6) 2: 03-14, 2015 (6) 3: 4-10, 2017 (8) 2: 11-23) has again changed his concept of the species of Gymnocalycium that live in the Sierras Bayas, moving it from G. schroederianum ssp. bayense = Echinocactus hyptiacanthus = Gymnocalycium hyptiacanthum (2001), to Gymnocalycium platense (Spegazzini) Britton & Rose! Even for the latter taxon, the application is controversial (Hunt et al. text: 132, 323; Charles 2009, 264). With regard to G. schroederianum ssp. boessii, probably a new name for the populations previously attributed to Gymnocalycium erolesii Neuhuber & C. A. L. Bercht, the surveys we carried out between the 21 and 24 November 2015 (A&M 1227, A&M 1237), between Vera and Berna, in the northern part of the Province of Santa Fe, Argentina, in the Humid Chaco ecoregion, we believe that this taxon only represents a variant with thinner spines than the type populations and to those of the Sierras Bayas. It is our opinion that G. schroederianum represents a case of an ex-dominant species, now with fragmented distribution (Anceschi & Magli 2018, 36: 76), that is, a taxon whose previous dominance and territorial continuity can be inferred on the basis of the current distribution, now with strongly fragmented populations usually due to anthropic intervention, as in the case of G. schroederianum. In the north, the populations are affected by deforestation as land is turned into agriculture (both arable and stock-breeding), as is now the case in the whole Chaco from Argentina to Paraguay. The populations of the center are subject to the same risks, to which is added the cultivation of Eucalyptus. In 2016, we could ascertain that in the Province of Entre Ríos, the areas crossed by the the Ruta 14 between Colón, Concordia and Chajarí are completely disfigurated by the cultivation of these plants, and that only south of Mocoretá, already in the Province of Corrientes, the first native "blanqueales" appear (Anceschi & Magli 2014, 13: 62), which then leave the fields in a northerly direction to the lands destined for grazing (i.e. pampa grasslands with rocky outcrops), between Curuzú Cuatiá and Mercedes, now with sporadic cultivation of Eucalyptus. It is to be considered that the central areas have also been affected by floods in recent years. The southern populations, as also highlighted by Papsch (2015 (6) 2: 12), which assigns them Conservation Status: Critically Endangered, CR, are affected, in the author’s words by "Massive mining of rocks for cement production …” and granite extraction. It is singular that populations belonging to the same species, no longer connected to each other due to anthropic intervention, are then considered as distinct taxa, sometimes with the relative separate assessments on the conservation status. This is the case of the populations of G. schroederianum, to which Charles (2009, 117, 119, 121), assigns three distinct degrees of risk, Near Threatened for ssp. schroederianum, Vulnerable for the ssp. bayense and Least concern for the ssp. boessii. Being a single natural species, we prefer instead to draw up for G. schroederianum a global risk assessment, that is Endangered, EN B2ab(i,ii,iii,iv). Justification: the area of occupancy of the global population is estimated to be less than 500 km2 (in the southern areas we are talking about just a few square meters), and based on what is known and observed, it was found that all populations are severely fragmented, and that in all areas a decline in extent of occurrence, area of occupancy, quality of habitat and number of locations can be inferred. (Quoted from Anceschi & Magli 2021, 89-91)