Rebutia (Aylostera) flavistyla was first published by Friedrich Ritter in Ashingtonia vol. 3(1): p.12, in 1978, though a photograph of the plant appeared in Ashintonia vo. 2(7) in 1976.

Confusingly, Ritter then published a fuller description in his “Kakteen in Südamerika”, vol. 2: pp. 615-6, in 1980, but called it Rebutia flavistylus.

The name R. flavistylus (or A. flavistylus) is sometimes given by nurseries to forms of Aylostera fiebrigii.

Here is the description in Latin and English as published. You should look up the original and subsequent publication for further details and photographs.

Rebutia flavistyla Ritter spec. nov.

Solitaria, viridis, 4-5cm crassa: costae 15-27. dissolutae tuberculis 4-6mm altis; areolae 1.5-3mm longae. oblongae, flaveolae vel albae. 4-6mm inter se remotae; spinae marginales flaveolae, postea albae. 15-22, tenues, 5-10mm longae, lateraliter directae: centrales complures similiter: flores ea. 3cm longi; ovarium squamis minimis. lana copiosa alba et saetis a Ibis instructum; stylus ea. 10mm cum tubo coal it us; sulcus nectarifer 1 mm longus: tubus floralis 9mm longus, obtectus ut ovarium; filamenta flaveola, sine lacuna insertiorum; stylus sulfureus. 8 stigmata citrina; petala 15mm longa. 4-5mm lata, spathulata. rutila; semina 1,2mm longa. 0,7mm lata. tenuiter tubercu lata; habitat infra Cajas, Prov. Mendez, Bolivia. FR 756.

Rebutia flavistyla Ritter spec nov.

Simple, green. 40-50mm wide; ribs 15-27, resolved into 4-6mm high tubercles; areoles 1.5-3mm long, oval. yellowish to white. 4-6mm apart; radial spines yellowish later white. 15-22. fine. 5-10mm long, sideways directed; numerous centrals similar; flowers ca. 30mm long; pericarp with very small scales, bearing copious white wool and white bristles: style connate with tube waII for 10mm; nectary 1 mm long; flower tube 9mm long, protected as for pericarp; filaments yellowish without any gap in insertion; style sulphur-yellow. 8 lemon-yellow stigma lobes; petals 15mm long, 4-5mm wide. spathulate, orange (rutile); seeds 1 .2mm long, 0. 7mm wide, finely tuberculate; habitat below Cajas, Prov. Mendez. Bolivia. Field number FR 756.