[Probable flora: an expression mean of ecological gradients in France]

The application of the criterion of fidelity of plants to plants over four millions botanical observations in France is considered to characterize the ecology of 215,000 phytosociological surveys. Among those discriminant plants, some are missing of the surveys, but they can have a certain probability of occurrence: these plants are called "probable plants" and they represent the "probable flora" of a territory. The study of their geographical distribution shows ecological gradients of flora across France in a better way than only considering the botanical observations. In fact, this method mitigates the discontinuities of taxa observations whose absence may be due to historical and/or anthropogenic factors.