Mammillaria marksiana aka "Snowy Pinecone Cactus"

Mammillaria marksiana is a small cactus. It belongs to the Cactaceae family. It comes from Mexico and grows in dry sites. Kew gives its range as Sonora to Zacatecas. LLIFLE lists Durango and Sinaloa. It doubts reports from southern Sonora. The plant grows on limestone cliffs and in low, dry forest. Plants nearby can give it shelter at these sites. Some groups grow in places that people struggle to reach.

The stem forms a round ball with a flat top. Wild plants reach about 0.2–0.3 feet (0.06–0.10 metres) tall. They span 0.16–0.39 feet (0.05–0.12 metres) in width. LLIFLE says plants grown in care can reach twice those sizes. Many stay single. Some grow side shoots, called offsets, and form clumps. Growth stays slow, even with care that suits the plant. The pale green stem can turn yellowish in strong light. It holds milky sap. Raised bumps called tubercles cover the stem.

White wool grows between the tubercles. It grows most thickly near the flowers. The thin spines range from golden yellow to brown. Spine counts vary, even on one plant. Young plants tend to have more spines than older ones. Some also have small spines that look like bristles. Flowers open by day in late winter or early spring. The greenish-yellow blooms form a ring on last year's growth. Each is about 0.05 feet (0.015 metres) across and long. The club-shaped fruits turn greenish or purplish red. They ripen in summer and hold small brown seeds.

This cactus grows well in pots. It can bloom without complex care. Outdoors, give it full sun or shade in the afternoon. Indoors, give it bright light with some direct sun. Strong light helps it grow flowers, wool and spines. It also brings out yellow tones. Use a very porous potting mix that lets water through. The pot must drain well too. Water through summer, but avoid excess water. Too much can rot the roots. Keep it dry through winter and safe from frost.

Do not water over the top. This can spoil the wool. LLIFLE advises a feed rich in potassium during summer growth. Its small, neat shape, wool and bright flowers add garden appeal. You can divide offsets to grow more plants. The supplied sources do not establish food uses or toxicity.