Family: Cactaceae
Compound: Mam tho
Geographic Origin: AZ, SON, SIN
Characteristics: A small, cylindrical clumping cactus similar to Mammillaria grahamii. The stems are green, growing from 5-15cm (2-6in) in height and 2-3.5cm (0.7-1.3in) in diameter, though clumps of stems can approach 30.5cm (12in) in diameter. Tubercles are prominent and cylindrical, though not often visible behind dense spines. The 14-23 white, radial spines effectively shade the skin of the plant, preventing sun damage and helping it to blend into the surrounding rock. They are straight to glabrous and interlacing. The 1-3 central spines on each tubercle are tan, fading to dark brown or black at the tip. The longest central spines form a hook at the end. Flowers are broadly funnel-shaped, white fading to a pink center with a distinct pink stigma that sticks out beyond the stamens. Flowers occur in a 'halo' around the top of stems. Blooming occurs from spring to fall but each flower only lasts about five days.
Natural History: Found in silty to sandy soils in flats or bajadas. Found between 152-762m (500-2500ft) in elevation. Typically underneath nurse plants such as creosote or mesquite.
Cultivation Notes: Easily grown from seed but can be propagated from offsets as well. If planting in the ground, a well-draining area beneath a small shrub such as creosote is recommended.
For general cactus and succulent propagation information, click here
Ethnobotany: Unknown for this species specifically, but fruit from other members of the genus was eaten fresh or dried.
Citations:
Seinet Arizona - New Mexico Chapter
https://swbiodiversity.org/seinet/taxa/index.php?taxon=Mammillaria+thornberi&formsubmit=Search+Terms
Center for Plant Conservation
https://saveplants.org/plant-profile/2795/Mammillaria-thornberi/Thornbe…