Spectrum Variability of Origanum vulgare L. (Lamiaceae, Magnoliopsida)

Origanum vulgare is a gynodietic species, in whose populations hermaphroditic individuals with bisexual flowers and female individuals with pistillate flowers grow to-gether. This is a holarctic forest-steppe species, a herbaceous perennial. The variability of the ratio of female to hermaphrodite individuals in 26 coenopopulations of O. vulgare from several habitats was investigated (in 8 populations by our own research in the Southern Siberia, and in 18 populations according to literature data from Eastern Europe). In all habitats the projective cover of the species was indicated by standard geobotanical methods. The plants studied have a long-root life form, therefore, a partial shoot or a partial shrub was used as a counting unit (an individual). The sexual structure of coenopopulations was studied by counting generative individuals on transects with an area of 10 to 20 m 2 . In each population the total number of individuals to be counted was at least 90. A significant positive correlation between the projective cover of O. vulgare in the phytocenosis and the proportion of female individuals in coenopopulations was found (the correlation coefficient r = 0.86, p = 0.001). ANOVA analysis has revealed no statistically significant difference in the proportion of females in 6 versions of various phytocenoses: F emp = 3.36 ( F crit5,5 = 5.1, p = 0.05). Considering features of the biomorphology and reproductive biology of various sexual individuals of O. vulgare , one can suggest that the increase of the projective cover of the species in the phytocenosis and the increase in the female individual proportion in the sexual spectrum depend on the successful growing of the seed regeneration in the phytocenosis.