Aylostera minor was first described (as Rebutia (Digitorebutia) diersiana var. minor Rausch) in Succulenta 58(11): pp. 258 – 259, in 1979 by Walter Rausch. It was thought to be a particularly small variety of R. diersiana. Found to be distinct enough to be given specific status by Mosti & Papini (2011).

Here is the description in Latin as published, with my own English translation. You should look up the original for more details as well as further notes in Dutch and a colour photograph.

Rebutia (Digitorebutia) diersiana var. minor Rausch var. nova

WALTER RAUSCH

Simplex vel paulum proliferans, brevicylindrica, 20 mm longa et 10-13 mm diametiens, glauca, radice napiformi parva: costis 10, recte adscenditibus vel paulum tortis, planioribus: areolis ovalibus, 1 mm longis, peranguste paene se tangentibus, fusco­ tomentosis; aculeis marginalibus 9-11, 4-5 paribus et uno deorsum directo, 1-2 mm longis, accumbentibus, violaceo-fuscis, basi obscuriore incrassatis, postea canescentibus: aculeo centrali 0. Floribus, fructu, seminibus  Digitorebutae diersianae Rausch modo.

Patria: Bolivia, Cinti meridiana, 3.600 m alt.

Typus: Rausch 630, depositus in Herbario Collectionis Plantarum Succulentarum Municipali Turicensi, Helvetia.

English translation

Rebutia (Digitorebutia) diersiana var. minor Rausch var. nova

WALTER RAUSCH

Single or branching a little, short cylindrical, 20 mm long and 10 – 13 mm diameter, glaucous, small tap root; 10 ribs, straight or slightly spiralling, flat; areoles oval, 1 mm long, closely packed to almost touching, with brown wool; 9 – 11 marginal spines, 4 – 5 equal pairs and 1 pointing downwards, 1 – 2 mm long, lying flat, purplish brown with darker, thickened base, later greyish; no central spine. Flower, fruit, seed as for Digitorebutia diersiana Rausch.

Habitat: Central Cinti, Bolivia, at 3,600 m altitude.

Type: Rausch 630 deposited in the Herbarium of the Municipal Succulent Plants Collection in Zurich, Switzerland.