INTRASPECIFIC MOLECULAR VARIATION IN HIERACIUM SECT ALPINA (ASTERACEAE), AN APOMICTIC GROUP

Intraspecific variation of four agamospecies of Hieracium sect. Alpina was studied using RAPD and isozyme techniques. No variation in either multiprimer RAPD or multi-enzyme phenotypes was observed within H. ho losericeum, suggesting that this widespread species consists of only a single genotype. A low level of within-population isozyme variation w as seen in H. tenuifrons and H. calenduliflorum, the origin of which a ppears to be consistent with somatic mutation. Most isozyme and all RA PD variation in these two species was partitioned between populations. A strong correlation with geography suggests that its cause may be du e to polytopic (=polyphyletic?) origin or perhaps to mutation and disp ersal. The most variable species was H. alpinum, in which isozyme vari ation occurred mostly within populations rather than between them, sug gesting occasional sexual events or that the parents of H. alpinum wer e heterozygous. RAPD variation in this species, in contrast, was parti tioned between Scottish and Swiss populations, suggesting the existenc e of geographical races.