Mammillaria muehlenpfordtii aka Mammillaria Celsiana

Mammillaria muehlenpfordtii is a cactus known as golden pincushion cactus. It belongs to the cactus family, Cactaceae. Its native range covers northeastern Mexico and extends to Jalisco. Records include Guanajuato, Querétaro, and San Luis Potosí. It grows in desert or dry shrubland. Recorded sites lie 5,577–7,874 feet [1,700–2,400 metres] above sea level. Mammillaria celsiana is a synonym of this species.

Young plants have one rounded stem. With age, each head can split into two. Repeated splits form clumps, sometimes with dozens of heads. Each stem becomes more upright and cylindrical with age. Stems reach about 0.33–0.49 feet [0.10–0.15 metres] tall, sometimes more. Their width ranges from 0.23–0.49 feet [0.07–0.15 metres]. The skin can be dark green, blue-green, or grey-green. The top has a shallow hollow filled with wool.

Cone-shaped tubercles cover the stems, with wool and white bristles between them. The small, round areoles bear wool when young. Each carries 24–50 short radial spines. These white or yellowish bristles almost hide the stem. Usually four longer central spines point out from each areole. They are stiff, pale yellow, and may curve back. The lowest spine is longest and can turn grey with brown tips.

Small flowers appear in summer, forming a ring near each head's top. They grow from the previous year's stem growth. Flowers range from carmine to rose-red, with red-brown outer petals. Each measures about 0.03–0.05 feet [0.010–0.015 metres] long. The fruit is red, and the seeds are brown. This species flowers readily and grows fast compared with other round cacti. Good conditions can produce large clumps within a few years.

This cactus needs no unusual care when grown on its own roots. Use a very porous cactus mix with good pot drainage. Neutral to slightly alkaline soil suits it. Water well during active growth, but avoid excess water. Rot is a risk, and winter care calls for dry soil. Small pots are preferred; larger pots need less water. A high-potassium feed suits summer growth. Frost can damage plants, though dry conditions may reduce harm. A winter rest at 8–12°C offers safer conditions. Propagation methods include seed, division, and grafting. Keep young seedlings out of full sun.