Note: The assessment Near Threatened, NT of the  the IUCN assessors (Cáceres, F., Pinto, R., Ostalaza, C. & Roque, J. 2017. Eriosyce islayensis (amended version of 2013 assessment). The IUCN Red List of Threatened Species 2017. Downloaded on 15 May 2018), do not consider many places in the Peruvian coastal area where populations of the species live, without threates due to urban developments, as for example: N of Matarani (Arequipa), Chala Viejo (Arequipa), Chinca (Ica), Coayllo-Omas (Lima) etc.
July 2021

Hunt et al. (2006, text: 109) divided Eriosyce islayensis (C. F. Förster) Kattermann into three ssp., adding to the type subspecies, Eriosyce islayensis ssp. grandis (Rauh & Backeberg) G. J. Charles & Eriosyce islayensis ssp. omasensis (Ostolaza & Mischler) G. J. Charles. The ssp. grandis, as Islaya grandis Rauh & Backeberg, had previously been correctly considered a synonym of E. islayensis by Anderson (2001, 298), an opinion then confirmed in Anderson & Eggli (2011, 261), where  E. islayensis ssp. grandis was also added to the synonymy (2011, 261). Regarding  ssp. omasensis, the last two authors continue to recognize it in the rank of species as Eriosyce omasensis (Ostolaza & Mischler) Ostolaza (Anderson 2001, 302; Anderson & Eggli 2011, 265). In our opinion, given the continuity of the large area occupied by the populations in the coastal area of the Peruvian desert (i.e. Departments of Arequipa, Ica, Lima, Moquegua, and Tacna), and the slight morphological variations between these (see A&M 1146, Arequipa, north-east of Matarani; A&M 1147, Arequipa, Chala, Chala Viejo; A&M 1206, Ica, Chincha, east of Chincha; and A&M 1210, Lima, north-east of Coayllo), configurable in the normal diversity found within a dominant natural species, we have decided to consider the above ssp. as simply synonyms of E. islayensis. (Quoted from Anceschi & Magli 2021, 64-65)