Note: In the cactusinhabitat edition 2010, the Gymnocalycium population of Young, now identified with Gymnocalycium uruguayense, was incorrectly attributed to Gymnocalycium schroederianum Osten. (December 2012)

To understand which name to assign to the populations of the dominant species in the genus Gymnocalycium Pfeiffer ex Mittler, spread over almost the whole territory of the Republic of Uruguay, and partially in neighbouring territories (Argentina: Corrientes and Entre Ríos, Brazil: Rio Grande do Sul), a short chronicle of the interpretation in the recent literature of the taxa involved is useful. In Anderson (2001, 354, 357, 363) Gymnocalycium hyptiacanthum (Lemaire) Britton & Rose, Gymnocalycium netrelianum (Monville) Britton & Rose and Gymnocalycium uruguayense (Arechavaleta) Britton & Rose, are considered distinct species. In Hunt et al. (2006, text: 129, 131, 135, 323) it is only G. uruguayense that remains, to identify the populations in question. G. hyptiacanthum was abandoned to be of controversial application, and the neo-typification of Kiesling (1999, 2: 444) rejected as contrary to ICBN Art 57.1. In turn G. netrelianum has been abandoned as being of uncertain application. In Cactaceae Systematic Initiatives (2008, 24: 21-25) about the taxa in question, Charles and Meregalli give a different opinion from the NCL. In summary, among the populations that occupy more or less discrete areas within the range of the species, there is a degree of recognisability, related to the differences in the characteristics of the spination. The neo-typification of G. hyptiacanthum made by Kiesling is considered correct, and the taxon has been reclassified into three subspecies: hyptiacanthum, netrelianum and uruguayense. The same approach is then reconfirmed by Charles (2009, 45-51). Here the Key to the subspecies of G. hyptiacanthum (Meregalli) as published on CSI 24: 22. On page 24, Meregalli informs us about the variation and distribution of the ssp. of G. hyptiacanthum: “The population of G. hyptiacanthum from the eastern part of Uruguay are here assigned to ssp. netrelianum. The plants differ from those of the typical subspecies mainly for the completely yellow-grey spines, lacking a red base. It is a relatively variable taxon, which in the southern part of its range merges progressively into ssp. hyptiacanthum, whereas towards north it is more similar to ssp. uruguayense. The attribution of the specimens from the central and northen part of the range to this subspecies is questionable: There is in fact a rather continuous clinal change between the plant with the typical traits of ssp. netrelianum and those of the subspecies ssp. uruguayense.” And more: “At the border with Brasil, near Acegua, a very interesting form was found. It is here referred to ssp. netrelianum, mainly for yellow spines, although there are some differences, namely the sub-campanulate yellow flower. This subspecies intergrades with ssp. hyptiacanthum in the southernmost part of the range, and with ssp. uruguayense in the central-western part of the range...”. From the words of the author, it would be plausible to taxonomically distinguish, populations that gradually merge into each other, and that are indistinguishable in many areas. Given that two subspecies probably to exist should benefit from a minimum of territorial autonomy, we think that in an idea of biological species, considered as a process and not as a static unit, composed of populations, themselves composed of individuals, variables and not by types, it is evident that populations which merge into one another are to be considered as belonging a single taxon or clade. It is difficult for us to think that there are populations distinguishable within a natural species, on the main evidence that the spines are more or less red at the base. In this regard, the photo illustrating G. hyptiacanthum ssp. netrelianum (Monville ex Labouret) Meregalli on CSI (2008, 24: 23), taxon that should be recognized to have the spines completely yellow, shows a plant with reddish base of the spines. In any case, in the era of molecular analysis, we think that certain distinctions could involve more the collectors' world than that of the biology. Given that we are talking about a single taxon, what name should we identify it by? The right publication should be given to Echinocactus hyptiacantus, described in 1839 by Lemaire, but in an incomplete manner and without a precise geographical indication. The neo-typification by Kiesling (1999) has tried to fix the application of the name, at least in the interpretation made by some collectors and South American botanists (Meregalli 2010, 1: 4-5, 11, 17). But apart from Kiesling‘s interpretation, there is also another by Papsch of 2011, which is deemed correct even by Charles (2009, 46). Papsch considers the Kiesling‘s neotype invalid, and suggests that E. hyptiacanthum can be referred to the species described as Gymnocalycium schroederianum Osten, registering a new neotype, and proposing G. hyptiacanthum = G. schroederianum. The latest interpretation of the name is by Till & Amerhauser (2010), who in turn reject the neo-typification of Kiesling, bringing back the idea that G. hyptiacanthum is linked to the species now known as G. schroederianum. As in the case of Gymnocalycium quehlianum (F. Haage ex Quehl) Vaupel ex Hosseus / Gymnocalycium stellatum Spegazzini, we think that the different interpretations are equally plausible, but this, and what it implies, creates confusion. Therefore, in agreement with Hunt et al. (2006, text: 129, 131, 135, 323), we prefer the use of the less controversial G. uruguayense to identify the populations in question, and we consider the names G. hyptiacanthum and G. netrelianum, and the homotypic related synonyms, controversial in their application. (Quoted from: Anceschi & Magli 2013b, 67-70)