The original description of Rebutia (Aylostera) rubiginosa was published in Taxon 12:1 (1963) p.29, the journal of the International Association for Plant Taxonomy, IAPT by Friedrich Ritter. The description is rather brief but was expanded upon in English in the Cactus and Succulent Journal of Great Britain 1965(3), p. 58, and repeated (in German) in Ritter’s self-published book “Kakteen in Sudamerika, volume 2” (1980), p.p. 608-9 with a black-and-white photograph on p. 784.

Here is the description in Latin as published, together with my own English translation, and a summary of the additional notes from the English expansion. You should look up the original descriptions for more details.

Rebutia rubiginosa (subg. Aylostera) Ritter, sp. nova

A R. tuberosa Ritter (cf. speciem praecedentem 1) recedit: corpore applanato, parce proliferante; areolis brunneis; spinis rubiginosis, 3-6 mm longis, radialibus 12, centralibus 4; flore 3 cm longo; ovario setis rubiginosis obsito; tubo florali 4-5 mm longo, tepalis 17-18 mm longis, 3-4 mm latis; staminibus 4-6 mm longis, coccineis.

Habitat: Below Challamarca, South Cinti province, Chuquisaca, Bolivia, 2800m. Collected as FR767.

English translation

Rebutia rubiginosa (subg. Aylostera) Ritter, sp. nova

Differs from the preceding described species (Rebutia (Aylostera) tuberosa) as follows: flattened body, somewhat proliferating; areoles brown; reddish-brown spines, 3-6mm long, 12 radials and 4 centrals; flower 3cm long; ovary covered with reddish-brown bristles; flower tube 4 – 5mm long, petals 17 – 18mm long and 3 – 4mm wide; stamens 4 – 6mm long, scarlet.

Additional notes

Body: Barrel-shaped with depressed crown, about 2-3 cm thick; epidermis dark green; single or only
sparingly sprouting, with a rather large, soft and often forked rootstock.
Ribs: Completely resolved into rounded tubercles, 2-3 mm broad and high.
Areoles: Brownish, oval, raised above the tubercle, ca. 2 mm long and about 2 mm apart.
Spines: All evenly rust coloured, becoming in age grey, mostly straight, fine needle-like, radials ca. 12 from 3-6 cm long; about 4 centrals, hardly longer and thicker than the radials.
Flowers: Laterally placed, opening at dawn for several days, closing at night; scentless; ca. 3 cm long and
opening to 2.75 cm wide; observations based upon a single bloom.
Pericarp: Olive green ca. 4 mm long and 3 mm broad, with a few 1-2 mm long, very narrow flesh-coloured
to green scales, bearing a small quantity of white wool flock and fine, soft, ca. 4 mm long, rust coloured bristles in the scale axils. Style connate with the receptacle wall for 8 mm above the pericarp, this part of the receptacle is tubular and only 2 mm thick.
Receptacle: 4-5 mm long, funnel form opening 4 mm wide, interior almost carmine, exterior pale olive brown with sparse but similar scaling as for the pericarp and broader scales.
Filaments: Carmine, lower deeper coloured, upper paler; the lowest 4 mm long; the uppermost 6 mm;
upright. Insertion over the lower half of the receptacle wall and on the corollla. Anthers light yellow, all at equal height. Pollen golden yellow.
Style: Light green, 17 mm long, of which 2 mm are the 6, light green, blunt, somewhat clenched stigma
lobes, exserted beyond the anthers.
Perianth: Wide opening; segments, 16-18 mm long; 3-4 mm broad, almost spathulate, broadest at three-
quarter length, very narrow at base, upper part short tipped and often on the margins somewhat indented. Colour intense vermilion. (Din 6164 Farbe 7 F); the outermost segments with a somewhat greenish midstripe, resolve into the receptacle scales.
Fruit and Seed: Unknown.