Concerning sexual polymorphism in Nepeta L

The sexual structure of the population of gynodioecic species Nepeta pannonica L. was studied during 8 years in the Central Black Earth Biosphere Reserve and the Kungur Forest Reserve (Perm region). The proportion of female forms in populations was slightly higher in the first study area (24 versus 17.1%). In Nepeta parviflora Bieb. the sexual structure of populations and seed productivity were studied during 5 years in the reserves Askania-Nova and Khomutovskaya Steppe. The proportion of females in natural populations was high (62-63%) and almost the same in both areas of the study. The study of the seed productivity of both sexual forms proved that the seed reproduction of this species is mainly realized through the female form. Hermaphroditic form is characterized by almost complete absence of seed set. Its flowers are morphlogically bisexual but mainly perform only donor function to androsterile flowers of the female form, supplying them with pollen. This is a sub-dioecious (functionally dioecious) plant, the sexual polymorphism of which is noted for the first time in the literature.