cy·ath·i·um 
(sī-ăthē-əm)
(sī-ăthē-əm)n.
An inflorescence consisting of a small cuplike structure enclosing a female flower and several male flowers, characteristic of plants in the genus Euphorbia, such as the poinsettia.
[New Latin, from kuathion, diminutive of kuathos, ladle.]