: North of Quarai, Rio Grade do Sul. Field number: FR 1386
Habitat and ecology: The cactus grows on rocky outcrops and stony fields in pampa grasslands. Frailea aureispinaSN|3524]]SN|3329]], grows together with Frailea castaneaSN|3329]]SN|3524]].

• Frailea pygmaea subs. aureispina (F.Ritter) P.J.Braun & Esteves
• Astrophytum aureispinum (F.Ritter) Halda & Malina
• Frailea aureispina F.Ritter

• Frailea pygmaea (Speg.) Britton & Rose
• Astrophytum pygmaeum (Speg.) Halda & Malina
• Frailea pygmaea var. aceguaensis Prestlé
• Frailea pygmaea var. albispina
• Frailea pygmaea subs. altigibbera (F.Ritter) P.J.Braun & Esteves
• Frailea pygmaea var. altigibbera F.Ritter
• Frailea pygmaea var. applanata Prestlé
• Frailea pygmaea var. argenta Prestlé
• Frailea pygmaea subs. asperispina (F.Ritter) P.J.Braun & Esteves
• Astrophytum asperispinum (F.Ritter) Halda & Malina
• Frailea asperispina F.Ritter
• Frailea pygmaea var. atrofusca Backeb.
• Frailea pygmaea subs. aureinitens (Buining & Bredero) P.J.Braun & Esteves
• Astrophytum aureinitens (Buining & Bredero) Halda & Malina
• Frailea aureinitens Buining & Bredero
• Frailea pygmaea subs. aureispina (F.Ritter) P.J.Braun & Esteves
• Astrophytum aureispinum (F.Ritter) Halda & Malina
• Frailea aureispina F.Ritter
• Frailea pygmaea var. auricantha Prestlé
• Frailea pygmaea var. bagensis Prestlé
• Frailea pygmaea var. brunneo-mollispina hort.
• Frailea pygmaea var. cabucaensis Prestlé
• Frailea pygmaea var. carpinteria Prestlé
• Frailea pygmaea var. castaneoidea Prestlé
• Frailea pygmaea var. catiensis
• Frailea pygmaea var. corallina Prestlé
• Frailea pygmaea var. curvispina F.Ritter
• Frailea pygmaea var. dadakii (Frič ex A.Berger) Backeb.
• Astrophytum dadakii (Frič ex A.Berger) Halda & Malina
• Echinocactus dadakii Frič ex A.Berger
• Frailea dadakii Frič ex A.Berger
• Frailea oreopygmaea var. dadakii (Frič ex A.Berger) Prestlé
• Frailea pygmaea var. elegantissima
• Frailea pygmaea var. gemmrichii Prestlé
• Frailea pygmaea var. gloriosa Prestlé
• Frailea pygmaea var. grandiflora
• Frailea pygmaea subs. hyssooniana Prestlé
• Frailea pygmaea var. insignia Prestlé
• Frailea pygmaea var. krausiana Prestlé
• Frailea pygmaea var. largoensis Prestlé
• Frailea pygmaea subs. lilalunula (F.Ritter) P.J.Braun & Esteves
• Frailea pygmaea var. lilalunula F.Ritter
• Frailea pygmaea var. longispina F.Ritter
• Frailea pygmaea var. maior F.Ritter
• Frailea pygmaea var. minanensis
• Frailea pygmaea var. mollispina-brunnea Prestlé
• Frailea pygmaea var. montana Prestlé
• Frailea pygmaea var. olimarensis Prestlé
• Frailea pygmaea var. planicosta F.Ritter
• Frailea pygmaea var. pulcherrima (Arechav.) Prestlé
• Astrophytum pulcherrimum (Arechav.) Halda & Malina
• Echinocactus pulcherrimus Arechav.
• Frailea pulcherrima Speg.
• Malacocarpus pulcherrimus Britton & Rose
• Frailea pygmaea var. sakusiana
• Frailea pygmaea var. salascana
• Frailea pygmaea var. salusiana
• Frailea pygmaea var. santanaensis Prestlé
• Frailea pygmaea var. viridilunula Prestlé

• Frailea pygmaea subs. albicolumnaris (F.Ritter) Hofacker
• Astrophytum albicolumnare (F.Ritter) Halda & Malina
• Frailea albicolumnaris F.Ritter

• Frailea pygmaea var. aurea (Backeb.) Backeb.
• Astrophytum aureum (Backeb.) Halda & Malina
• Frailea aurea Backeb.
• Frailea oreopygmaea var. aurea (Backeb.) Prestlé

• Frailea pygmaea subs. fulviseta (Buining & Bredero) P.J.Braun & Esteves
• Astrophytum fulvisetum (Buining & Bredero) Halda & Malina
• Frailea fulviseta Buining & Bredero

: Frailea pygmaeaSN|3675]]SN|3317]] subs. aureispina firstly described as Frailea aureispinaSN|3634]]SN|3329]] by Friederic Ritter in 1970, is a very small cactus with shortly cylindrical stems covered by golden-yellow spines. It is usually included within (as a synonym of) Frailea pygmaeaSN|3329]]SN|3317]]. However, this taxon is the one that least resembles Frailea pygmaeaSN|3669]]SN|3317]], the dark felted areoles are similar to the areoles of Frailea phaeodiscaSN|3317]]SN|3669]], and the yellow to orange spines are noticeably stronger than those normally found in F. pygmaea.
Note: In the area North of Quarai where Frailea aureispinaSN|3317]]SN|3329]] grows, no other forms of F. pygmaea grow, but Frailea schilinzkyanaSN|3329]]SN|3634]] (Frailea perumbilicataSN|3317]]SN|3675]]) is quite common. This latter species also has strong spines, which vary from yellow to dark brownish in colour, but other than in these characteristics it does not resemble F. aureispina. It is possible that F. aureispina is not related to F. pygmaea at all, its characteristics being the result of natural hybridization between F. phaeodisca and F. schilinzkyana (F. perumbilicata), both of both of which grow nearby. This is just a hypothesis, but clearly this is a plant that needs to be studied in more detail.
Stems: Cylindrical, bright green, 15-25 mm thick, 3-5 cm high, solitary.
Root: Napiform.
Ribs: 13-18, 0.5-1 mm tall, dissolved in round tubercles, only 0.5-1 mm high.
Areoles: On the tubercles, 0.8 mm long, 0,5 mm wide, with reddish-brown felt, later naked, 1-1,5 mm apart.
Spines: Pale to orange yellow with a reddish-brown base.
Radial spines: 10-13, 3-4 mm long, acicular, usually straight, all around the areole, spreading sideways or partly erected.
Central spines: Absent, or 1-2, protruding, not longer than radials, similar in colour or brownish.
Flowers: Apical, 4 cm long, and over 4 cm wide when fully open, pericarpel 7 mm long, 4 mm thick above, tapering below, tawny brown with small narrow reddish scales, dense grey wool, and reddish-brown fine bristles. Nectaries absent. Flowers tube 8 mm long, 10 mm wide above, pale yellow internally, externally yellowish-green covered as the ovary. Filaments pale yellow, red at base, set up to 2 mm below the upper edge of the tube. Anthers pale yellow. Stylus about 2 cm long, pale yellow, the lowest 2 mm united with the tube with c. 6 pale yellow stigma-lobes 6-7 mm long. Petals 22 mm long, 3-4 mm wide, greenish yellow.
Seeds: Cap-shaped, nearly black, shining, light, 1,5 mm long, 2 mm wide.