Rebutia (Aylostera) hoffmannii was first described by L. Diers and W. Rausch in Kakteen und andere Sukkulenten 28(5): p. 105-6, the journal of the Deutsche Kakteen-Gesellschaft, in 1977.
The description is reproduced here in the original Latin as published, together with my own translation in English. You should look up the original for extensive further notes in German plus a colour photograph.
Rebutia (Aylostera) hoffmannii
DIERS et RAUSCH spec. nov. L Diers und Walter Rausch
Corpus saepe simplex, globosum, aetate progrediente subelongatum et proliferans, ad 35 mm diametiens, clara-viridis; costis ca. 23, spiraliter tortis, in gibberes 2-3 mm longos divisis; areolis rotundis, ca. 1 mm diametientibus, albido-fusco-tomentosis; aculeis marginalibus et centralibus haud discriminandis, divaricate-patentibus, ca. 40, 5-10 mm longis, setosis, vitreo-albis saepe fusco-acuminatis.
Floribus ad 40 mm longis et ad 45 mm diametientibus; ovario globoso, fusco-roseo, receptaculo violaceo-albis tecto; phyllis perigonii exterioribus roseo, squamis fusco-roseis, pilis et setis lanceolatis, violaceo-roseis; phyllis perigonii interioribus late-lanceolatis, interdum serratis, longe-acuminatis, aurantiacis; fauce, filamentis, stylo albis, ceptaculo connato. Fructu globoso, 5 mm stigmatibus 4-5 flavidis, stylo cum rediametiente, ochraceo, squamis obscurioribus, pilis et setis albis tecto. Seminibus Aylosterae typo.
Patria: Argentina, Salta, prope Santa Viktoria.
Typus: Rausch 521 A , depositus in Herbario Collections Plantarum Succulentarum Municipali Turicensi, Helve.
English translation
Rebutia (Aylostera) hoffmannii
DIERS et RAUSCH spec. nov. L Diers und Walter Rausch
Body often single, spherical, elongating and proliferating with age, up to 35mm in diameter, bright green; ca. 23 ribs, twisting spirally, split into tubercles 2 – 3mm long; areoles round, ca. 1mm in diameter, with brownish-white wool; no distinction between ca. 40 marginal and central spines, spreading and projecting, 5 – 10mm long, bristly, glassy white, sometimes with brown tips.
Flowers up to 40 mm long and 45 mm in diameter; ovary spherical, brownish-pink, flower tube violet-pink above; outer petals lanceolate, pink, with brownish-pink scales, purplish-pink hairs and bristles; inner petals broadly-lanceolate, sometimes serrated, long-acuminate, orange; throat, filaments and style white, the latter fused with the flower tube, and 4 – 5 yellowish stigmas. Fruit spherical, 5 mm in diameter, ochre with darker scales, white hairs and bristles. Seeds typical of Aylostera.
Habitat: near Santa Viktoria, Salta, Argentina.
Collection number (Type): 521 A, deposited in the Collection of the Municipal Succulent Plant Herbarium in Zurich, Switzerland.