Eriosyce aconcaguensis (F.Ritter) P.C.Guerrero & Helmut Walter, 2024

Walter, Helmut E., Cadiz-Veliz, Aron, Merino, Beatriz M., Villalobos-Barrantes, Heidy M. & Guerrero, Pablo C., 2024, Taxonomic dissection based on molecular evidence of the Eriosyce curvispina complex (Cactaceae): identifying nine endemic species from Central Chile, PhytoKeys 237, pp. 117-139 : 117

1. Eriosyce aconcaguensis (F.Ritter) P.C.Guerrero & Helmut Walter comb. nov.

Pyrrhocactus aconcaguensis F. Ritter, Succulenta (NL) 9: 108. 1960. Basionym.

≡ Pyrrhocactus aconcaguensis F.Ritter in Succulenta (Netherlands) 1960: 108. 1960 syn. sec. Tropicos ≡ Horridocactus aconcaguensis (F.Ritter) Backeb., Cactaceae 6: 3791. 1962 syn. sec. Tropicos ≡ Eriosyce curvispina var. aconcaguensis (F.Ritter) Katt., Eriosyce (Cactac.) Gen. Revis. Ampl. 1: 117. 1994 syn. sec. Kew WCVP (2019) ≡ Neoporteria curvispina var. aconcaguensis (F.Ritter) Donald & G.D.Rowley in Cact. Succ. J. Gr. Brit. 28: 55. 1966 syn. sec. Kew WCVP (2019) ≡ Pyrrhocactus horridus var. aconcaguensis (F.Ritter) F.Ritter, Kakteen Südamerika 3: 948. 1980 syn. sec. Kew WCVP (2019) ≡ Pyrrhocactus curvispinus var. felipensis F.Ritter, Kakteen Südamerika 3: 932: 1980 (nom. inval. Art. 34.1, 37.1). In our text, "syn. sec." refers to the source that assigns a synonym to the concept of either the accepted name or one of its homotypic synonyms sensu Korotkova et al. (2021).

Type.

Chile, Southern America, Valparaíso Region, Catemu, Chagres , June 1955, F. Ritter 542 (Holotype: U 0249247, digital image!). (Image available at https://bioportal.naturalis.nl/en/specimen/U__0249247) .

Iconography.

F. Ritter, Succulenta (NL) 9: 108. 1960 (as Pyrrhocactus aconcaguensis ); A. Hoffmann & H.E. Walter, Cact. Fl. Sylv. Chile 2nd Ed., Lam. 71a (as Eriosyce curvispina var. aconcaguensis ) 2004.

Morphological notes.

Stems globose, 8-12 cm. diameter, sometimes elongating with age. Roots fascicular. Ribs 17-21, 1.5 cm high, obtuse. Areoles 1.5 × 0.6 cm., 1.0-1.5 cm apart. Spines grey, thickly aciculate, mostly straight, or somewhat curved; radial ones 7-12, 1-3 cm long, central ones 4-6, to 4 cm long. Flowers 4-5 cm, funnel-form; pericarpel green, not much elongated, bract-scales small, axils with inconspicuous white hairs; nectary tubular; style white with 14 whitish stigma-lobes; perianth segments yellow, usually with a faint reddish mid-stripe, 0.6-1.2 cm broad. Fruits barrel-form, 1.5-2.5 cm long, reddish, bract-scales as for the pericarpel; perianth remnant attachment area wide, basal pore large. Seeds blackish, 1.2 × 1 mm; testa finely tuberculate, coarsely ribbed; hilum oval; micropyle in a groove.

Distribution.

Endemic species occurring in the middle Río Aconcagua Valley, between Llay-llay and San Felipe (32°S, 70°W) at elevations generally between 500 and 700 m.

Conservation status.

The extent of occurrence (EOO) of E. aconcaguensis is estimated to be less than 100 km2, with fewer than 5 known localities. The species range is severely fragmented, and there has been a decrease in population size and the number of localities due to landscape anthropization. Additionally, there has been a loss of habitat quality due to the expansion of the agricultural and mining industry. The population from the type locality at Chagres (Llay-llay) is likely extinct due to the replacement of xerophytic vegetation by extensive cultivation of avocado trees on slopes between Llay-llay and San Felipe. Therefore, we propose to classify the species as Critically Endangered (CR) according to the criteria (2017) B1ab(i,iii,iv).