Origin
The Mammillaria senilis is a species of cactus that has its origin in Mexico. Specifically, this prickly plant grows in the states of Hidalgo and Querétaro where they adapt to the rocky mountain terraces. This plant is also known as the 'Old Man Cactus' due to its distinctive appearance.

Characteristics
The Mammillaria senilis is a compact and slow-growing cactus that is recognisable by its spiral-shaped, cylindrical shape. The cactus is known for its spiral-shaped surface covered in woolly, white hairs reminiscent of an old man's beard. The flowers of the Mammillaria senilis are carmine red to deep purple and usually appear in late spring. The fruits that follow are bright red in colour and contain small brown seeds.

Care
The care of the Mammillaria senilis requires some basic knowledge of cactuses. As a high-altitude-tolerant plant, it prefers a full sun or half-shade position. Watering should be moderate, with a dry rest period in the winter to promote blooming. The plant is frost sensitive and should be placed indoors if the temperature falls below 10 degrees Celsius. The Mammillaria senilis requires well-draining soil to avoid root rot.