Geometric Rarity: Euphorbia decaryi

A subterranean marvel featuring rippled, bronze-tinted foliage and a spreading rhizomatous habit for the specialized enthusiast.

1. Origin & History of Name: The genus Euphorbia is named after Euphorbus, the Greek physician to King Juba II of Numidia, who famously used the plant’s caustic latex for medicinal purposes. The specific epithet decaryi honors Raymond Decary, a French botanist and administrator who extensively collected flora in Madagascar during the 1920s and 1930s, significantly expanding Western knowledge of the region's unique succulents.
2. Morphology: This species is a small, rhizomatous succulent that spreads horizontally via underground stems. The epidermis of the leaves is deeply undulated or "crinkled," a morphological adaptation that may help break up light and reduce transpiration. The foliage often exhibits a metallic, purplish-bronze pigmentation under high light. Its flowers, known as cyathia, are inconspicuous and bell-shaped, surrounded by brownish bracts that mimic the surrounding soil and leaf litter.
3. Habitat & Origin: Euphorbia decaryi is a wild species endemic to the southern coastal regions of Madagascar, particularly around Tolagnaro (Fort Dauphin). It thrives in dry, littoral forests and scrublands. Due to habitat loss, it is listed under CITES Appendix II, meaning commercial specimens should be sourced from nursery-propagated stock to ensure environmental sustainability.
4. Cultivation Profile:
   • Substrate: Requires a highly porous, mineral-heavy substrate. A mix of 60% grit (lava rock or coarse sand) and 40% organic compost is ideal for preventing moisture retention around the sensitive rhizomes.
   • Light: Thrives in bright, indirect light or dappled sunlight. In the Indian subcontinent, protect from harsh midday sun during peak summer to prevent leaf scorch; an east-facing balcony is often perfect.
   • Water/Dormancy: Provide regular watering during the growing season (March–September), allowing the mix to dry completely between applications. Reduce water significantly during the cooler winter months as the plant enters a period of reduced metabolic activity.
5. Scientific/Historical Anecdote: Unlike many of its upright, thorn-heavy African relatives, Euphorbia decaryi has evolved a "creeping" growth habit. This allows it to occupy the niche of ground cover in its native habitat, effectively creating a micro-environment that traps moisture and protects its root system from the intense Malagasy sun—a survival strategy known as an isohydric response.