本文報導原產墨西哥之新歸化種－禾葉大戟(Euphorbia graminea Jacquin)，目前已歸化於臺灣南部屏東縣。禾葉大戟與大戟屬其他物種可藉由其葉互生；葉狀苞對生，線形；種子卵圓形，角狀，表面具縱向之深斑點狀凹陷加以區別。本文提供本植物的形態描述、繪圖及彩色照片。

Euphoribia graminea Jacquin, a species of the Euphorbiaceae native in Mexico, has naturalized in Pingtung county, southern Taiwan. E. graminea can be easily distinguished from the other species of genus Euphorbia as leaves are alternate, leaf-bracts are opposite and linear, seeds are ovate-rounded, angular and its surface are deeply punctuate with pits in regular longitudinal rows. This paper provides a description of the species, line drawings and color photographs to aid in identification.