ABSTRACT
Euphorbia millii Desmoulins is a perennial shrub with thick woody stems bearing stout spines and a few obovate leaves near the tips of the shoots. The flowers are borne in axillary cyathia, typical of the genus Euphorbia, and each cyathium is subtended by two conspicuous, bright-red ovate bracts. Euphorbia millii is a qualitative SDP at temperatures of 20°Celsius or higher, and has a critical daylength of approximately 12.5 hour, though this may vary with temperature as in other Euphorbia, species. Flower development occurs most rapidly at temperatures from 25 to 30°Celsius, but although bracts are formed at 30°C they become white and fail to develop their attractive red color.
