To determine the corolla shape, 1 digit is coded. It is evaluated on a fully open flower, if necessary by blowing on the beam of a flower held between the fingers to expand it fully. There are three alternatives to evaluate: 1st alternative, while blowing the geometric shape of the outer edge of the set of the 5 petals that make up the corolla is examined and compared with the scheme to assign the value as appropriate (it is the simplest alternative but blowing longer to expand the entire flower and at altitudinal levels where oxygen is lower, this is important for the evaluator); 2nd alternative, while blowing, the external edge between two contiguous acuminates is examined by passing an imaginary line between these extremes or contiguous acuminates (blue line in the diagrams), if the imaginary line is parallel to the examined edge of the corolla, i.e. the imaginary line is confused with the examined edge, we are facing the pentagonal shape that has value 5, if there is deficiency to reach the imaginary line (gray triangular areas towards the central part of the corolla, observe Fig. 5), then we are in front of 2 possibilities: semi-stellate whose value is 3, when the deficiency is minor and stellate whose value is 1, when the deficiency is major; if on the contrary there is excess that is to say the edge of the corolla exceeds the imaginary line (gray areas of semi-circular segments towards the external part of the corolla, see Fig. 5), then we are facing 2 other possibilities: rotated whose value is 7, when the excess is lower and very rotated whose value is 9, when the excess is higher; normally potato flowers are pentamerous, but sometimes hexamerous (anomalous) flowers are present, in this situation this alternative is better applied (it is the most accurate alternative and less time is blown to expand only one side of the corolla); 3rd alternative, consider the relationships L and B, where: B = petal width, L = length from petal junction to acumen. To achieve these relations it is necessary to expand the corolla and sometimes it is necessary to herborize, that takes time and labor, besides the relations L<<<B and L<<<<<B, are not very rational, so the use of this alternative is not recommended