<div>Gynodioecy has been identified to occur in the herbaceous polycarpic<i>Origanum vulgare</i> ssp. <i>gracile</i> growing in Tajikistan and is
here described in detail for the first time. The investigated
populations of <i>O. vulgare</i> ssp. <i>gracile</i> form two types of
flowers, perfect and pistillate, on different individuals. In pistillate
flowers, stamens are represented by staminodes. The size of many parts
of the corolla and androecium of perfect flowers is significantly larger
than in pistillate flowers. Four criteria have been identified that make
it possible to reliably distinguish flowers of different sexual forms:
the size of the corolla and its parts, the difference between calyx tube
length versus corolla tube length, the position of the anthers, and the
rate of development of stamens. Perfect flowers are characterized by
strictly pronounced protandry. According to the pollen/ovule ratio (from
825 to 953), <i>O. vulgare</i> ssp. <i>gracile</i> is facultatively
xenogamous. Hermaphrodites predominated (from 58.9% to 76.2%) in five
of the investigated populations. The frequency of females in <i>O.
vulgare</i> ssp. <i>gracile</i> was shown to be most dependent on annual
precipitation (Bio12). Finally, we discuss the presence and distribution
of gynodioecy within the genus <i>Origanum</i> and its adaptive
significance for the existence of populations of <i>O. vulgare</i> ssp.<i>gracile</i> .</div><div>Key words: gynodioecy, <i>Origanum vulgare</i> ssp. <i>gracile</i> , sex
ratios.</div>