Pseudolithos cubiformis
Pseudolithos cubiformis
Cube Pseudolithos
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Taxonomy
Family Apocynaceae · Genus Pseudolithos
Description
Pseudolithos cubiformis is a tiny, cube-shaped succulent from Somalia that looks like a living stone. It grows very slowly, thrives in bright light, and demands an ultra-fast-draining, mostly mineral mix. Treated like a warm, arid-climate cactus, it rewards careful growers with bizarre, starry flowers that attract flies.
Common Names
Cube PseudolithosCubic Stone PlantLiving Cube
Context
nativeRegion
Arid limestone plains and stony flats of northeastern Somalia (Horn of Africa).
usdaZones
11b–13 (best grown indoors or in a warm greenhouse outside the tropics)
companionPlants
Huernia spp., Stapelia spp., Orbea variegata, Edithcolea grandis
culturalUses
Primarily a collector’s ornamental and botanical curiosity; no well-documented traditional uses.
Care
Care Requirements
LightVery bright light to bright filtered sun; 4–6 hours gentle direct sun (AM/late PM). Indoors, a sunny south/west window or bright grow lights.
WateringExtremely sparing. Water only in warm weather after the mix is bone-dry; roughly every 2–4 weeks in summer. Keep nearly dry in winter to prevent rot.
SoilUltra-fast-draining, mostly mineral mix: 70–90% pumice/lava/grit with 10–30% inorganic fines; very little or no peat. Shallow pot with large drainage.
FertilizerDilute, low-nitrogen cactus feed at 1/8–1/4 strength once a month in active warm growth. None in cool/dim periods.
HumidityLow and airy (ideally <40%). Provide strong airflow; avoid stagnant, humid spaces.
TemperatureWarm: 75–95°F (24–35°C) ideal. Absolute minimum 55°F (13°C), drier if cooler. Protect from cold and cool-wet conditions.
Growth & Life Cycle
HabitMiniature, cube/knob-shaped succulent; solitary when young, sometimes branching with age.
Mature Size1–4 in (2.5–10 cm) across and tall, typically on the small end in pots.
Growth RateVery slow growing.
BloomingWarm-season to late summer/autumn; small, star-shaped, carrion-scented stapeliad flowers that attract flies.
DormancySemi-dormant in cool, short-day months; keep much drier and warmer than typical winter conditions.
Propagation
MethodsSeed, Grafting onto stapeliad rootstock (e.g., Stapelia, Huernia, Ceropegia)
DifficultyAdvanced
Best SeasonLate spring through summer in stable warmth and bright light.
Maintenance & Notes
PruningNo pruning needed; remove spent flowers and any desiccated tissue with sterile tools.
RepottingInfrequent—every 2–3 years or when roots fill the pot. Repot in warm weather into a dry, sterile, mineral mix; water lightly after 1–2 weeks.
Pests & DiseasesRoot/collar rot from excess moisture; root mealybugs, mealybugs, and fungus gnats in damp media. Ensure sterile mix, dryness, and airflow.
ToxicityLikely mildly toxic/irritant latex if ingested or in contact with skin. Keep away from pets and children.
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