Aiming to obtain a mathematical equation, which by the linear dimensions of the leaf blades, would allow to estimate the leaf areas of Cissampelos glaberrima, the relations between real leaf area (Sf) and leaf blade dimensional parameters, such as length of the main vein and the maximum width (L) perpendicular to the main vein, were studied. The simple linear, exponential and geometric equations can be used for estimation of the leaf area for the weed Cissampelos glaberrima. From a practical viewpoint, it is suggested to choose the simple linear equation of the regression model, using the C*L, applying the equation Sf = 0.7878 (C*L), which is equivalent to taking 78.78% of the product between length of the main vein and the maximum width, with correlation coefficient of 0.9307.
weed; leaf area; Cissampelos glaberrima
