Growth analysis of French serradella plants was made by classical and functional methods. Relative Growth Rate, Leaf Area Ratio and Unit Leaf Rate were calculated on the basis of weekly measurements of dry matter and leaf area quantities. The dry matter accumulation in above-ground part of serradella plants was described by logistic functions. Their characteristics included the inflection points of the first and the second derivatives, the standard errors of parameters, the determination coefficient and the residual mean squares. The linear function, which was obtained after linearisation of the logistic function, allowed for confirmation of the hypothesis of statistical differentiation among behaviour plants of serradella growing in different conditions within the whole vegetation period.