IntroductionCapparis herbacea Willd. (C. spinosa auct. non L.) is a perennial pendulous shrub distributed in the Irano-Turanian floristic region, extending into the Euro-Siberian region, the Middle East, Central Asia, and the Caucasus (Inocencio et al., 2006). Capers from the section Capparis L. (which also includes C. herbacea) usually inhabit desert and semidesert areas (Fakhireh et al., 2012). In Georgia this species grows in dry open woodlands, xerophytic scrublands, semideserts, and secondary steppes. As a native plant it is of considerable importance for erosion control and revegetation of degraded habitats in Georgia, due to its drought tolerance and ability to withstand desertification in the fragile semiarid ecosystem.Capparis herbacea differs from the Mediterranean C. spinosa L. by straight stipules, prominent innervations of the abaxial leaf surface, strong zygomorphy of the flower, and star-like shape of the nectary. Like C. spinosa, C. herbacea is an economically important species; capers, pickled flower buds and young fruits, are often used as seasoning or garnish. The available data on the sexual system of the section Capparis indicate that at least one species from the section C. spinosa is an andromonoecious plant (Zhang & Tan, 2008).Andromonoecy is a particular sexual system in which both perfect (hermaphrodite, bisexual) flowers are produced with male (staminate, female sterile) flowers on the same individual. This rare phenomenon is described only in 1.7% of Angiosperms (Yampolsky & Yampolsky, 1922;Diggle, 1991;Miller & Diggle, 2003). Our preliminary observations indicate that C. herbacea produces both hermaphrodite and staminate flowers on the same individual.The aims of the present work were to determine morphological and morphometric differences between 2 flower morphs, study variations in the proportion of male and hermaphrodite flowers during the flowering season, and investigate whether andromonoecy occurs in Capparis herbacea. According to the classification of section Capparis L. revised by Inocencio et al. (2006), C. herbacea is regarded as C. sicula Veill. subsp. herbacea (Willd.) Inocencio, D. Rivera, Obón & Alcaraz. The number of stamens and the size and shape of the anther and nectary are regarded as important diagnostic characters. The species is known to be a nocturnal plant; however, factors affecting the time and duration of the blooming period have not yet been identified. Therefore, the second purpose of this study was to identify the characters mentioned in the studied Abstract: Floral morphology coupled with the morphometry of androecium revealed that Capparis herbacea Willd. has an andromonoecious sexual system, producing both male and perfect flowers on the same plant. Functionally male flowers develop more stamens with larger anthers than bisexual ones (63.6 ± 0.6 and 4.1 ± 0.01 mm; 58.1 ± 0.7 and 3.6 ± 0.02 mm, respectively). The ratio of male to perfect flowers ranges from 0.5 to 2.6 during the flowering season. The development of dense trichomes on the adaxial surfac...