Clonal structure and reproductive biology in the gynodioecious herb Glechoma hederacea L. Lamiaceae

Abstract: Clonal structure and reproductive biology in the gynodioecious herb Glechoma hederacea L. Lamiaceae The frequencies of females, hermaphrodites and partially male-sterile (PMS) genets of Glechoma hederacea were estimated in natural populations in S Sweden. The frequency of females and PMS genets in natural populations varied from 0 to 100%. The temporal and spatial variation in stamen fertility in PMS genets was studied in the field and in cultivation. Hermaphrodite flowers were self-compatible, seed production was found to be pollen limited and the clonal structure of the species usually caused a reduction in seed set in females. Hermaphrodite and PMS clones were usually larger than female clones and more heterozygous. Disomic inheritance of duplicated loci was found in this tetraploid species, and segregation ratios for allozymes conformed to Mendelian expectation. Allozymes were used to establish multilocus genotypes in seven populations in S Sweden and three populations in the S Czech Republic. Clonal diversity in an area of c. 100 m2 was greatest in an ephemeral population (PD i.e. proportion of distinguished genets = 0.98) and lowest in more stable habitats (PD = 0.01). Little evidence of intermingling of different genets was found.