Pattern of variation of agamospermous Limonium (Plumbaginaceae) in the British Isles

An investigation of cytological, palynological, and taxometric variation in Limonium binervosum (G. E. Sm.) C. E. Salmon has revealed an extensive pattern of hierarchical relationships within this agamospermous group in the British Isles. The group is either triploid (2n = 27) or aneuploid tetraploid (usually 2n = 35) with a highly jumbled karyotype. Pollen is either not produced or of very low stainability (in the range 0–38%). Well stained pollen grains are usually abnormally large resulting from a failure of a meiotic division. These facts as well as the presence of only a single self-incompatible polledstigma morph in the majority of the group suggest that it is obligately agamospermic. The very strong correlation of taxometric relationship and geographical distance between variants suggests that evolution in the group has occurred by the gradual accumulation of mutations giving rise to morphologically and geographically related seed clones. The hierarchical pattern of variation as revealed by cluster analysis has been used as the basis of a hierarchical classification of the group.