Subspecies, varieties, forms and cultivars of plants belonging to the Frailea pygmaea group

• Frailea pygmaea (Speg.) Britton & Rose: is a very small cactus that lives half buried in the ground. It has a wide distribution and is very variable with some forms having heads no wider than one or two cm. Distribution: Argentina, Brazil and Uruguay.
• Frailea pygmaea subs. albicolumnaris (F.Ritter) Hofacker
• Frailea pygmaea subs. asperispina (F.Ritter) P.J.Braun & Esteves: has dark felted areoles and golden-yellow spines stronger than those normally found in F. pygmaea. Distribution: North of Quarai, Rio Grade do Sul.
• Frailea pygmaea var. aurea (Backeb.) Backeb.: has golden-yellow spines, yellowish or brown areoles and sulphur-cleistogamous fruits. distribution: Uruguay near Montevideo. (Dept. Canelones, Puenta-Ballena?)
• Frailea pygmaea subs. aureinitens (Buining & Bredero) P.J.Braun & Esteves
• Frailea pygmaea subs. aureispina (F.Ritter) P.J.Braun & Esteves
• Frailea pygmaea var. curvispina F.Ritter: it has recurved, creamy-brown bristles, short to long, more or less curved backwards, twisted and interlaced. Distribution: Pantano Grande Region, Rio Grande do Sul.
• Frailea pygmaea var. dadakii (Frič ex A.Berger) Backeb.: has globular stems, depressed on top, with about 12 ribs. It branches profusely forming dense clumps. The spines are all radial, usually 8, brownish passing to white, curved backwards and twisted.
• Frailea pygmaea subs. fulviseta (Buining & Bredero) P.J.Braun & Esteves
• Frailea pygmaea var. gloriosa Prestlé: has long glassy-white spines and brown areoles. It is very nice.
• Frailea pygmaea var. grandiflora: has somewhat larger flowers. Distribution: Uruguay.
• Frailea pygmaea subs. lilalunula (F.Ritter) P.J.Braun & Esteves