Mammillaria thornberi, commonly known as Thornber’s fishhook cactus or Thornber’s nipple cactus, is a perennial succulent native to the desert regions of the Southwestern United States and Northwestern Mexico. It thrives in arid environments, often found on rocky slopes and desert plains where it forms part of the unique desert scrub ecosystem. This cactus typically grows in clumps with cylindrical stems that can reach up to 10 centimeters in height and 3.5 centimeters in diameter, though some may grow as tall as 30 centimeters. Each stem is adorned with up to 21 radial spines and one to three central spines that are characteristically hooked.

The flowers of Mammillaria thornberi are particularly notable after heavy rainfall, showcasing white or pink inner tepals with pink midstripes, and can be up to 3 centimeters wide. The bright red fruit is not only a visual highlight but also edible, containing black seeds. This cactus is valued in cultivation for its drought tolerance and unique appearance, making it a popular choice for rock gardens, xeriscaping, and as a potted plant for enthusiasts of arid-landscaping. It requires minimal water, well-draining soil, and can tolerate partial shade, though it prefers bright light conditions. While it has no major disease issues, overwatering can lead to root rot. It is also important to note that while it is not typically invasive, care should be taken to prevent its spread in non-native habitats.CC BY-SA 4.0