Relationships Among Some Populations of Anthoxanthum alpinum and A. odoratum (Poaceae, Pooideae): a Morphological/Anatomical Approach

The genus Anthoxanthum s.l. (including Hierochloë) (Poaceae, Pooideae, Aveneae) comprises 35– 50 species and has a cosmopolitan distribution. Anthoxanthum alpinum was described as a diploid perennial that is distributed in northern Eurasia and in the high mountains of central and eastern Europe. Difficulties in finding reliable morphological differences between this taxon and the widespread tetraploid A. odoratum have resulted in taxonomists treating them as conspecific, despite the cytological differentiation. The purpose of this study was to provide information that may help clarify the relationships between these taxa. Macromorphologial, micromorphological, and anatomical data were gathered and analyzed for 14 populations representing both taxa from Scandinavia and the Iberian Peninsula. Statistical analyses were carried out to identify the most useful characters for taxonomy. The relationships among samples were based on different similarity coefficients and summarized using UPGMA clustering methods. The results show that geography has more statistical weight than ploidy level in explaining the relatedness among individuals and populations. A strong correlation between leaf micromorphological/anatomical characters and environmental parameters was detected. The results of the analyses do not support recognition of A. alpinum as a distinct species.