Abstract Aeschimann, D., N. Rasolofo & J.-P. Theurillat (2012). Analysis of the flora of the Alps. 3: biology and phenology. Candollea 67: 5–21. In French, English and French abstracts. The third in a series, this paper continues the statistical analyses of the data published in «Flora alpina», focusing on that which concerns the biology (longevity, biological forms and plant height) and phenology of taxa. Expressed as percentages, the results concerning the flora are envisaged globally, by vegetation belt, by administrative division and by floristic contingent. Several cartographic patterns are presented and it is shown that, in the Alps, the percentage of annual taxa is positively correlated with the relative weight of the Mediterranean contingent, as well as with the taxonomic richness. Inversely, the percentage of perennial taxa is negatively correlated with the same data. The results confirm the predictive value of the percentages of chamaephytes in bioclimatology. Overall, more than 63% of the taxa ...