Karyological analysis of the five native MacaronesianFestuca(Gramineae) grasses supports a distinct diploid origin of two schizoendemic groups

[摘要] A karyological analysis has been conducted of all five native MacaronesianFestucagrasses belonging to fine-leavedF.subg.Festucasect.Aulaxyperand broad-leavedF.subg.Drymanthelesect.PhaeochloaLoliinae lineages. Chromosomal analyses were made in 30 plants corresponding to 17 populations of the fineleavedF. agustinii, F. jubata, F. francoiandF. petraeaand 2 populations of the broad-leavedF. donax . All counts except one tetraploid count were diploids, showing 2 n= 14 chromosomes. Diploidy was confirmed for the robustF. donax , nested within a clade of relict ancestral fescues as reported in recent phylogenetic studies, and was also found in the more slenderF. agustinii, F. jubata, F. francoiandF. petraea , which are basal to a recently evolved clade of polyploid red fescues. Karyotypes of the two groups are however distinct, with broad-leavedF. donaxshowing larger and more regular chromosomes and all four fine-leaved taxa showing smaller and more irregular submetacentric chromosomes. Our karyological data indicate that these two groups of diploid fescues correspond to distinct schizoendemics which apparently originated at different times after independent continental colonizations of Macaronesia.

[学科分类] 植物学

[关键词] diploidy;Festuca agustinii;F. donax;F. francoi;F. jubata;F. petraea;karyology