Epithelantha micromeris (Engelm.) F.A.C.Weber ex Britton & Rose
Button Cactus, Ping Pong Ball Cactus
Cactus micromeris, Echinocactus micromeris, Mammillaria micromeris,
This species is native to the United States (Arizona, New Mexico, and Texas) and northeast Mexico.
Epithelantha micromeris is a small cactus with spherical, egg-shaped, or short cylindric, usually solitary stem covered with clusters of grayish or purplish-white spines with brown bases, collectively appearing as a brown spot at the center of each cluster. The stem grows up to 2 inches (5 cm) tall and up to 1.6 inches (4 cm) in diameter. The density of the spines gives the stem illusion of being ashy gray and rough in general aspect. Tubercles are hemispheric to short cylindric, up to 0.25 inches (0.3 cm) long, and arranged around the stem in spiral rows, each tipped with an areole that bears 20 to 40 spines in 1 to 3 series. Flowers are small, pink to white, rarely yellow, and appear partially obscured by longer spines at the stem apex from late winter to early spring. The attractive edible fruits are bright red, narrowly cylindric, and contain several black seeds.
USDA hardiness zones 8b to 11b: from 15 °F (−9.4 °C) to 50 °F (+10 °C).
How to Grow and Care
To encourage better flowering, allow the plants to enjoy a cooling period in the winter and suspend watering. Unlike many other cacti, which use their ribs as storage devices, Mammillaria feature raised tubercles, from which spines emerge. When you water, the tubercles expand to allow for increased water storage. The flowers emerge from the axils of these tubercles on the previous year's growth, which accounts for their interesting halo effect. The cactus mustn't be exposed to prolonged dampness and sitting water. Never let your cactus sit in a dish of water. Lastly, ensure to fertilize during the growing season for the best results.
Repot as needed, preferably during the warm season. To repot Mammillaria, ensure the soil is dry before repotting, then gently remove the pot. Knock away the old soil from the roots, removing any rotted or dead roots. Treat any cuts with a fungicide. Place the plant in its new pot and backfill it with potting soil, spreading the roots as you repot. Leave the plant dry for a week or so, then begin to water lightly to reduce the risk of root rot.
Learn more at How to Grow and Care for Mammillaria.
Subspecies and Forms
- Back to genus Epithelantha
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