Questa è una forma proliferante dell'Echinocactus grusonii ricoperta da lanuggine bianco-giallino e da corte spine gialle. La struttura a costole non è evidente, ma sono presenti tubercoli pronunciati che lo fanno assomigliare ad una Mammillaria.

Family: Cactaceae (Cactus Family)

Scientific Name:  Echinocactus grusonii forma mostruosa

Origin:  Garden origin (Nursery produced cultivar)

Conservation status: Listed in CITES appendix 2.

Vernacular Names:

• Monstrous Golden barrel cactus,
• Monstrous Golden ball cactus,
• Monstrous Mother-in-law's-seat,
• Monstrous Mother-in-law's-cushion.

E. grusonii forma mostruosa 

Description: This is a free offsetting small form of E. grusonii that  is covered by yellowhish-white wool with short yellow spines. The rib structure is not yet apparent, and they have pronounced tubercles making them look superficially like Mammillarias. With age they will form large crowded clumps.

Cultivation: Frost tender but cold hardiness increases with improved drainage, so keep plants as dry as possible in winter. Provide the plant with extremely well-drained soils, as plants are subject to crown and soft rot if they remain too moist. They grow best in full sun or half shade, which will help to maintain the lustre of the spines and plants compact.  They are prone to mealy bug and red spider mite.
Frost Tolerance: Light frost protection required for safe cultivation, but can tolerate sporadic light frost.
Diseases and pests: Watch for infestations of mealybug, scale insects and spider mite.

Propagation: From cuttings (but it is difficult to grow this plant on its own roots) or preferably by grafting.