Scientific Name: Conophytum calculus

Common Name(s): Marble Buttons, Button Plants, Cone Plants, Dumplings, Living Pebbles (The name "calculus" is derived from Latin for "pebble" or "stone," referring to its distinct rounded shape).

Defining Characteristics:

• This plant consists of 2 leaves completely fused into a single smooth, hard, spherical, or globose body, ranging from chalky grey-green to pale yellowish-green
• The surface is completely smooth, hairless, and opaque, typically without spots, dots, or markings
• The top features a tiny, narrow slit (about 4mm) from which flowers emerge, often resembling a "mouth" or "buttonhole"
• It forms dense, dome-shaped cushions or compact mats, with older plants often creating clusters of many bodies
• Small, fragrant, golden-yellow to dark orange, or sometimes ivory/peach flowers can be produced in autumn. The flowers are nocturnal, opening at night to attract moth pollinators with a strong clove or carnation scent.
• In summer, it develops a dry, papery sheath from the previous season's leaves. This natural cocoon protects the internal green body from heat during dormancy until it breaks in autumn to reveal new growth.

Recommended Pot Size: Small 

Josh’s Frogs offers a wide variety of supplies for all of your indoor gardening needs.

Temperature Requirement (°F): Conophytum calculus thrives in temperatures between 60-80°F, simulating its native arid and temperate habitat. It is quite cold-hardy for a succulent, capable of tolerating temperatures as low as 19°F, though it requires protection from extreme frost and high heat over 90°F.

Humidity: 40–50%

Watering Frequency: Water sparingly; the plant should be allowed to dry out completely between waterings during its active growth period (autumn to late spring). Keep them completely dry during summer dormancy. They are highly susceptible to overwatering, which causes rot.

Lighting: Bright, filtered, or indirect light is best to prevent the plant's leaves from curling due to sunburn.

Soil Type: 80–90% inorganic (pumice, lava rock, coarse sand) and 10–20% organic (cactus mix, coco coir). The mix must prevent moisture retention to avoid root rot.

Growth Rate: Very slow 

Height at Maturity: 1 inch in diameter and roughly 1 to 2 inches tall

Origin: Specifically restricted to the Knersvlakte region in the far north-west of the Western Cape Province, South Africa.

Regional Locality: It grows on open, stony plains and arid flats/hills. Found specifically among white quartz pebbles, which provide a cool, reflective surface for the plant.

USDA Hardiness Zone: 10a to 11b

Suggested Vivarium/ Animal Terrarium Use:

Care Notes: Conophytum calculus is toxic to both humans and pets, if consumed, as all parts of the plant contain calcium oxalate crystals. We deem this plant safe for use with the above animals, but the more risk-averse may wish to avoid it. For more information please visit the ASPCA list of Toxic and Non-Toxic Plants.

Shipping Notes: Generous LIVE ARRIVAL GUARANTEE offered.

As good practice, Josh's Frogs recommends washing all plants thoroughly, removing as much soil as possible with dechlorinated water before placing them in their final home. Live plants may vary in color, size, and appearance.

ALL PLANTS ARE SHIPPED IN POTS WITH SOIL OR OTHER MEDIA UNLESS IT IS DEEMED NECESSARY TO SHIP BARE ROOT.

Standard pot sizes for Josh's Frogs plants typically range from 1.25-3.5 inches.