Euphorbia denisiana is the kind of ‘wildcat’ species. Rauh (1995), in his excellent ‘succulent and xerophytic plants of Madagascar’ vol1, describes a species ‘close to E. ankarensis and E. alfredii’, but adds ‘ Unfortunetaly, the type locality is unknown and the herbarium material is very poor’.
While, MNHN collection indicates that Euphorbia denisiana is from massif of Antongona (Imerina). The information comes from R. Decary, April 3rd 1938. The only description in the herbarium is ‘ greenish yellow flower’. The dry plant remains and this description fit with Euphorbia found in the Antongona area.
Euphorbia denisiana grows in granitic cliffs of Antongona inselberg (25 km West Antananrivo).
Shrubs to 100cm in diameter, 100cm tall.Apical leaves and yellow to greenish yellow cyatha with red border, cyathophylls spreading, ovate, orange glands.