Fig. 5
From: Phenotypic variation of floral organs in flowering crabapples and its taxonomic significance
The floral trait screening system for Malus taxonomy. The floral trait screening system mainly consists of four steps: intraspecific uniformity test, interspecific distinctness analysis, principal component analysis and Pearson correlation analysis. The intraspecific uniformity of qualitative and quantitative traits was expressed by the mean mode frequency (\(\overline{MF}\)) and the mean coefficient of variation (\(\overline{C.v.}\)), respectively. And the interspecific distinctness analysis of qualitative traits was measured by the closeness of the mode frequency (MF) and theoretical frequency (\({1}\left/{f}\right.\)) of the rank that each trait shows in all taxa, while of quantitative traits was measured by the coefficient of variation (C. v.)