Solitary, strongly armed
Stem: Dark green, depressed globose, up to 13 cm in diameter, 6-7
Ribs: Deeply notched, with prominent, chin-like tubercles.
Spines: Subulate, stout, thick and curving, yellowish or amber-coloured with darker tips, becoming grey with age.
Central spine: 1(-2), 18 to 20 mm long.
Radial spines: 7-11, unequal, 6 to 22 mm long.
Note: The taxonomy of this species is not clear.
former synonym Gymnocalycium castelanosii (As indicated by
Backeberg) seems to be incorrect,
and Slaba also separated it from
Gymnocalycium hybopleurum (Gymnocalycium hybopleurum
v. ferox backbg). Prevalently, this controversial species is
now considered as Gymnocalycium mostii ssp. ferocior.
Photo of conspecific taxa,
varieties, forms and cultivars of plants
belonging to the
has lots of synonyms (
like many other cacti) whit
several controversial varieties and subspecies ):