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 uruguayense (Arechavaleta) Britton & Rose (1992)
MM231 - Cuaro, Artigas, Uruguay
Highslide JS        

Field number

MM231 - collected by Massimo Meregalli


Rio Grande do Sul


Arigas - northern of Cuaro


named of its origin 
flat globular, dark green
12–13 ribs, strongly tubercled
areoles initially gray
3 radial spines, to 0.8 in (2 cm) long, white
flowers ca. 1.6 in (4 cm) long, wide funnel shaped, petals pale greenish-yellow, inside whitish
seeds gray-black

Flowering time

June in cultivation
3–4 years from seed
Synonyms Echinocactus uruguayensis Arechavaleta (1905)
CITES Appendix II
Description of "Kakteen von A bis Z" by Walter Haage with courtesy by Kakteen-Haage made available.