Gymnocalycium Pfeiffer ex Mittler (1844)

(Greek gymnos = naked; Greek kalyx = calyx)
naked flower calyx
because of the calyx without spines, bristles and hairs

usually flat globular, in age some thick columnar, very different sizes, simple or clumping
ribs 20 or less; spines adjacent or outspread, thin to very strong
flowers small short to large funnel shaped, often white or white with a red center, however also yellow or red,
calyx bare and scaly; fruits and seeds very different

Highslide JS


south America - Bolivia, Paraguay, south Brazil to Argentinia
almost complete south America eastern of the Cordilleras
steppes and mountains

Growth period

warm and partly shady, full sun is to avoid, temporarily a location outdoor is possible
plants with stronger spines is possible to get more direct sunlight
from early summer on abundant watering, but permanent moisture is to avoid
especially at warm weather the plants require more moisture

Winter period

bright and cool, not to dry, at 6–12°C (42–53°F), as possible not colder than 5°C (41°F)
species which origin in mountains occasionally somewhat colder


nutrient rich, very permeable to water with addition of peat
Gymnocalycium achirasense H. Till & Schatzl ex H. Till (1987)
Highslide JS
  Highslide JS   Highslide JS


San Luis - near of Achiras in about 3280 ft (1000 m) altitude
between rocks and grass


named after its origin
globular to elongated globular, about 2.2 in (5.6 cm) high, 2.7 in (7 cm) Ø, gray-green
12–15 straight ribs, seperated in chinlike protrusions
areoles oval, initially slightly felted, soon bare
10–12 radial spines, straight to faintly arcuate, at the base dark, to the tip bright horn-colored,

about 1 in (2.5 cm) long, alike central spine, straight to somewhat bent
flowers funnel shaped, 2.3 in (5.8 cm) long, 2.8 in (7.1 cm) Ø, white with purple-pink midvein
style yellowish white with a twelvepart bright yellow strigma
seeds small

Flowering time

May in cultivation
November–December in habitat
5–6 years from seed


Gymnocalycium horridispinum var. achirasense (H. Till & Schatzl) Lodé (1995)
Gymnocalycium monvillei
ssp. achirasense (H. Till & Schatzl ex H. Till) H. Till (1993)
CITES Appendix II
Description of "Kakteen von A bis Z" by Walter Haage with courtesy by Kakteen-Haage made available.