Gymnocalycium saglionis, commonly known as the giant chin cactus, is a globular cactus species native to the Monte Desert and dry grasslands of northwestern Argentina. It features a dull-green to blue-green, almost cylindrical body that can become more or less flattened, reaching up to 40 cm in diameter and 90 cm in height. The spines, which can grow to 3−4 cm long, vary in color from yellowish-brown, reddish, or white, becoming grey over time, and provide an attractive contrast against the green body. There are typically 1−3 central spines and 10−15 radial spines that bend against the stem. Notably, the spines turn bright red when wet. The flowers, which are 1.4 inches (3.5 cm) long, can be white or reddish and often appear more than one at a time. The fruits are globular, reddish or dark pink, and split sideways to release tiny, shiny black-brown seeds.

The giant chin cactus is valued for its large size, thick curved spines, and slow growth rate, making it a favorite among collectors. It is cultivated worldwide as an ornamental plant, often found for sale. This species has been recognized with the Royal Horticultural Society’s Award of Garden Merit in the UK. It is well-suited for warm, part shady conditions, but can tolerate extremely bright situations. However, it is prone to sun scorch or stunted growth if overexposed to direct sunlight during the hottest part of the day in summer. In cultivation, it prefers full sun or part shade, very low to low water requirements, and well-draining soils.CC BY-SA 4.0