J. Saukel et R. Langer, THE ACHILLEA-MILLEFOLIUM-GROUP (ASTERACEA E) IN CENTRAL-EUROPE .1. INTRODUCTION, EVALUATION OF CHARACTERS AND PLANT-MATERIAL, Phyton, 31(2), 1992, pp. 185-207
A catalogue of morphological and anatomical characteristics is present
ed as a basis for a systematic revision of the Achillea millefolium-co
mplex. Detailed descriptions of quantitative parameters and critical d
ifferential characters, are presented. Field observations on ontogeny,
modification, phenology and cases of obvious local hybridogeneous gen
e flow are discussed.