Figure 5.

Standardized linear phenotypic selection gradient for a) the number of flowers and b) floral morphology in a hybrid population of Orchis militaris and O. purpurea . The selection gradient is illustrated with an added-variable plot, in which the residuals from a linear regression model of relative fitness on all traits except the focal trait are plotted against the residuals from a regression model of the focal trait on the other traits.

Jacquemyn et al. BMC Evolutionary Biology 2012 12:178   doi:10.1186/1471-2148-12-178
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