Thyrses 5 - 7 cm in diameter , sparsely flowered , with 2 - 5 white sterile marginal flowers about 2 - 3 cm in diam . ; peduncles 2 - 4 cm long ; fertile flowers yellowish white , corolla c . 3 mm in diam . , rotate , lobes ovate , half as long as corolla tubes ; stamens nearly as long as corolla , anthers oblong ; styles slightly higher than calyx teeth 聚伞花序直径5 - 7厘米，花稀疏，外围有2 - 5朵白色、直径2 - 3厘米的不孕花，总花梗长2 - 4厘米；可孕花花冠黄白色，直径约3毫米，辐状，裂片卵形，长约为筒之半；雄蕊与花冠几等长，花药矩圆形；柱头略高出萼齿。
