Endive, Chicory, and their wild relatives. A systematic and phylogenetic study of Cichorium (Asteraceae)

Abstract

This thesis describes a systematic and phylogenetic analysis of the genus Cichorium. Cichorium is a small genus within the Asteraceae family (tribe Lactuceae) and is well known because of its two widely cultivated species: C. endivia (endive) and C. intybus (chicory). The genus occurs in the Old World and has been introduced in temperate and semi-arid regions elsewhere. An important diagnostic character at the genus and species level is the unique structure of the pappus, which, at the same time, causes difficulties regarding the relationship of Cichorium with other Lactuceae genera because of the unknown homology of it with other pappus structures. From a morphological point of view the genus is thus rather isolated. Our molecular phylogenetic analyses based on chloroplast (RFLP and sequence data) and nuclear ribosomal (ITS sequence data) DNA of Cichorium and nine other genera ( Agoseris, Catananche, Chondrilla, Lactuca, Microseris, Prenanthes, Scolymus, Scorzonera and Taraxacum) confirm the isolated position of Cichorium within the Lactuceae.\nBesides the two cultivated species C. endivia and C. intybus, four wild species are recognised here: C. pumilum, C. calvum, C. bottae, and C. spinosum. The latter two species are easily distinguished by their cushionlike growth form and spiny terminal branches, respectively. The remaining two wild species are morphologically very similar to the two cultivated species C. endivia and C. intybus, because they differ primarily in quantitative features. However, in a multivariate analysis of morphological characters the species do not extensively overlap. The most important morphological character for species delimitation is the pappus, but the differences in life span and reproductive system help to distinguish C. intybus (selfincompatible perennial) from C. endivia, C. pumilum, and C. calvum (all selfcompatible annuals).\nThe results of the phylogenetic analysis of Cichorium based on both chloroplast and nuclear ribosomal DNA agree with the genetic relationships among the spec