裸萼球屬多肉植物，原產於阿根廷中部草原上。植株呈扁球形，表皮墨綠色，具有許多刺針；每個刺座有5枚灰色側刺。花生於球體頂端，夏季開花，花色白至粉紅，花徑4~8cm，是同屬植物中較大者。

A succulent plant of the genus Gymnocalycium, native to the grasslands of central Argentina. Oblate-spherical shape, dark green and densely spiny; each areole has 5 gray radial spines. Flowers white to pink, 4 - 8cm in diameter, bloom at the top of the sphere in summer.

栽培：全日照通風環境下可生長良好，日照充足時可促進開花。炎夏時切勿讓植株曝曬，以免產生日燒等曬傷跡象。為了防止爛根等情形，需採用排水透氣的介質。耐寒性強，保持介質乾燥可以耐低溫至-5°C。

The plant grows well with full sunlight and good ventilation. Sufficient sun exposure can promote flowering, however, exposure in high summer may cause signs of scorch, such as sunburn. Plant in draining and breathable soil to avoid root rotting. The plant is cold-tolerant and can withstand low temperature up to -5 °C if the soil is kept dry.

多肉植物因型態特殊，常被應用在植物推廣教育。本種花朵美麗，是強刺類仙人掌中以觀花為主的種類，常進行觀賞品種育種選拔。適合單盆種植以欣賞型態。

Succulents are often used in promotion and education because of its unique look. This plant is outstanding among hard-spined cacti for its ornamental flowers, so it’s often showcased in ornamental breeding selection. Suitable for a single-potted ornamental.