Evolution of Illicium (Illiciaceae): Mapping morphological characters on the molecular tree I.-C. Oh 1,2 , T. Denk 1 , and E. M. Friis 1 1 Department of Palaeobotany, Swedish Museum of Natural History, Stockholm, Sweden 2 Department of Systematic Botany, Evolutionary Biology Centre (EBC), Uppsala University, Uppsala, Sweden Received November 7, 2002; accepted March 28, 2003 Published online: September 17, 2003 Ó Springer-Verlag 2003 Abstract. Illicium is a member of the ANITA grade and as such represents one of the basalmost lineages of flowering plants. Mapping morpholog- ical characters on a recently published molecular tree sheds some light on the conflict between the traditional classification of Illicium based on floral structures and the molecular based phylogeny. Floral characters of Illicium, i.e. number, size, and shape of perianth segments, stamens, and carpels, are highly variable. In Illicium sepaloid perianth segments intergrade with petaloid ones. This is also observed in the other ANITA taxa, where grada- tions from bracts to perianth segments and stamens occur, but not in more derived plant groups, and indicates that the number of floral organs may not be genetically fixed in basal angiosperms. There- fore, floral characters may have evolved in parallel in different groups of Illicium and, taken alone, may be unsuitable for a subgeneric division of Illicium. In contrast, seed structures such as the hilar area and a conspicuous hilar rim structure found in New World species of Illicium support a major division between New World and Old World species of Illicium as suggested by molecular data. Epidermal features generally are uniform within the genus but provide some support for one of the clades recog- nized in the molecular tree. In general, few mor- phological characters can be used to distinguish natural species groups within Illicium. Key words: Illicium, star anise, seed morphology, leaf epidermis, hilar rim, fossil seeds, evolution. Molecular studies have provided new phyloge- netic models for basal angiosperms and a rigorous framework for discussing angiosperm evolution. The recognition of the ANITA grade consisting of three lineages, Amborellaceae, Nymphaeales, and Illiciales-Trimeniaceae-Au- strobaileyaceae, at the base of the angiosperm phylogenetic tree (Qiu et al. 1999, 2000; Soltis et al. 1999, 2000) is particularly interesting for discussing morphological characters in early angiosperms. The ANITA families are typically small, monotypic or consisting of only few genera, and except for the Nymphaeales they all have a restricted geographical distribution. The fossil record supports the antiquity of ANITA lines with unambiguous Early and mid-Creta- ceous finds of Nymphaeales (Friis et al. 2001) and Illiciaceae (Frumin and Friis 1999). The fossil record of the Illiciaceae further demon- strates that this ANITA family also had a more extensive geographical distribution in earlier geological periods. Fruit, leaf and seed fossils of different periods during the Late Cretaceous and Early Tertiary have been described from Plant Syst. Evol. 240: 175–209 (2003) DOI 10.1007/s00606-003-0022-1