Origin and Habitat: Rebutia patericalyxSN|5044]]SN|5044]] has been reported from La Cueva, Chuquisaca, Bolivia.

• Rebutia patericalyx F.Ritter
• Aylostera patericalyx (F.Ritter) Mosti & Papini

• Rebutia spegazziniana Backeb.
• Aylostera spegazziniana Backeb. in Backeb. & F.M.Knuth
• Echinorebutia spegazziniana Backeb.
• Rebutia froehlichiana Rausch
• Aylostera froehlichiana (Rausch) Mosti & Papini
• Rebutia fusca F.Ritter
• Aylostera fusca (F.Ritter) Mosti & Papini
• Rebutia mamillosa Rausch
• Aylostera mamillosa (Rausch) Mosti & Papini
• Rebutia mamillosa var. australis F.Ritter
• Rebutia mamillosa var. orientalis F.Ritter
• Rebutia patericalyx F.Ritter
• Aylostera patericalyx (F.Ritter) Mosti & Papini
• Rebutia rubiginosa F.Ritter
• Aylostera rubiginosa (F.Ritter) Backeb.
• Rebutia spegazziniana var. atroviridis (Backeb.) Šída
• Rebutia spegazziniana var. boliviensis n.n., Rausch
• Rebutia boliviensis hort.
• Rebutia sumayana Rausch
• Aylostera sumayana (Rausch) Mosti & Papini
• Rebutia tarijensis Rausch
• Aylostera tarijensis (Rausch) Mosti & Papini
• Rebutia tarvitaensis F.Ritter
• Aylostera tarvitaensis (F.Ritter) Mosti & Papini
• Rebutia tuberosa F.Ritter
• Aylostera tuberosa (F.Ritter) Backeb.
• Rebutia vulpina F.Ritter
• Aylostera vulpina (F.Ritter) Mosti & Papini
• Rebutia fiebrigii var. vulpina hort.
• Rebutia vulpes F.Ritter
• Rebutia waltheriana Backeb.
• Aylostera waltheriana (Backeb.) Y.Itô
• Rebutia zecheri Rausch
• Aylostera zecheri (Rausch) Mosti & Papini
• Lobivia atrovirens var. zecheri (Rausch) Rausch

Description: Rebutia patericalyxSN|4953]]SN|5044]] Ritter (1977) is one of the controversial forms of the widespread and variable Rebutia spegazzinianaSN|5044]]SN|5033]]. It is noted for the smallish solitary to sparingly clustering stems. The spines are 3 to 6mm long, pointing sideways, pale yellow to white and covered by minuscule hairs visible only under lens. The flowers are scarlet. However the distinguishing characteristics of Rebutia patericalyxSN|5033]]SN|5044]], appear to fall within the natural variation of Rebutia spegazzinianaSN|5044]]SN|5033]] and most authors synonymize it with the latter, but it still has a value for a collector because they identify plants with particular characters. Regrettably most plants in cultivation under this name seldom match up to the original description, being usually raised from commercial seed which has often been wrongly identified, and this is sadly often the case with Ritter plants.
Derivation of specific name: 'patericalyx', from Latin 'patera', bowl, and Latin 'calyx', calyx, cup, a bowl-shaped cup, and refers to the shape of the flower.
Stems: Single-stemmed to sparsely clustering, green, 1.3 to 3 cm wide.
Ribs: 13 to 16 ill-defined.
Areoles: 1-2 mm long, with white wool.
Spines: 12-15, pale yellow to white, pointing sideways, 3 to 6mm long, sometimes with one similar central spine. All with tiny pubescent hairs visible only with a magnifying glass,
Flowers: Scarlet , 3.5 cm or more cm long and wide. Pericarpel with white wool and bristles.
Note: Rod and Ken Preston-Mafham (1997) proposed a different classification and placed Rebutia patericalyxSN|5033]]SN|5044]] as a synonym of Rebutia deminutaSN|5044]]SN|4953]] (Web.) Br.& R.

Bibliography: Major references and further lectures
1) John Pilbeam “Rebutia” Cirio Pub. Services, 01 May 1997
2) Rod and Ken Preston-Mafham “Cacti: The Illustrated Dictionary” 1997

Cultivation and Propagation: It is easy to grow and recommended for beginners. Prefer gritty, porous mix with a pH slightly on the acidic side. Full sun to light shade, Water regularly in summer but do not overwater (the root system is rot prone) and allow the pot to dry out between waterings. Keep dry in winter Hardy to -4°C it will take low temperatures when dry and do require a winter rest period. This species will occupy a small flower pot comfortably and remain a manageable sized house plant.
Pest and disease: This plants are subject to mealy-bug attack and to fungus and rot problems brought about by overwatering and high humidity.
Propagation: Seed or offsets.