Unclumped log Ṁ vs. log Γ_e. Solid line: relation for O stars. The different symbols indicate stellar sub-classes following Sect. 4.1. Dashed line: the steeper slope of the Of/WN and WNh stars. The kink occurs at log Γ_e = −0.58. The grey asterisks indicate the position of the stars with Y> 0.75 under the assumption of core He-burning. The grey upside down triangles are stars from Mokiem et al. (2007) which have only an upper limit in Ṁ and are excluded from the fit.