Rebutia (Aylostera) mixticolor was first described by Friedrich Ritter in Kakteen und andere Sukkulenten 28(4): p. 77, 1977, the journal of the Deutsche Kakteen-Gesellschaft. In addition, Ritter published further details of the description in his book “Kakteen in Sudamerika”, Vol. 2, p. 604 (1980).

In the original description, the petal colour is described as “mixed purple and fiery red”. In the book, this is expanded on (in German), my English translation of which is: “colour throughout, cinnabar (7), created by mixing purple (10) with orange-red (9); outer petals with a stronger mixture of purple.” Numbers refer to the Biesalski colour chart (1957). Sadly the only illustration is a black-and-white photograph.

Here is the description in Latin as published, followed by my own English translation. You should look up the original for more details.

Rebutia mixticolor Ritter spec. nov.

Solitaria, in apricatione vilocea [sic], 2—4 cm crassa, humilis, radice rapacea; costae 11—13, 3-5 mm altae, valde crenatae; areolae 2 mm longae, subnudae, 5—8 mm inter se remotae; spinae solum marginales, lateraliter directae, brunneae, postea albae, 3-7 mm longae, 6-11.

Flores 3-4 cm longi ; ovarium lana alba et plerumque saetis albidis instructum; stylus 1—5 mm cum tubo coalitus, sulcus nectarifer 1-3 mm longus; tubus floralis 6—13 mm longus; filamenta rosacea; stylus viridis, stigmata 6-8 flavoviridia vel flava; petala 14—20 mm longa, 5—9 mm lata, spathulata, coloribus mixtis purpureo et igneo; semina atrobrunnea, 1,5 mm longa, vix tuberculata; habitat San Antonio, Prov. Mendez, Bolivia.

Sammelnummer FR 1108

English translation

Rebutia mixticolor Ritter spec. nov.

Solitary, violaceous in open sun, 2 – 4 cm thick, small, tap-rooted; 11 – 13 ribs, 3 -5 mm high, deeply furrowed; areoles 2 mm long, almost bare, 5 – 8 mm apart; 6 – 11 marginal spines only, spreading laterally, brown, later whitish, 3 – 7 mm long.

Flowers 3 – 4 cm long; ovary with white wool and distributed with whitish bristles; style fused to the tube by 1 – 5 mm, nectary groove 1 – 3 mm long; floral tube 6 – 13 mm long; stamens pink; style green, with 6 – 8 yellowish-green or yellow stigmas; petals 14 – 20 mm long and 5 – 9 mm wide, spatulate, of mixed purple and fiery red; seeds dark brown, 1.5 mm long, not very warty; habitat San Antonio, Prov. Mendez, Bolivia.

Collected as FR 1108.