Sexual polymorphism and spatial segregation of Thymelaea hirsuta in Liguria (north-west Italy)

摘要

Flowering phenology, sexual polymorphism and spatial segregation were studied over two consecutive years in a population of Thymelaea hirsuta (L.) Endl. (Thymelaeaceae) growing on coastal cliffs in north-western Italy. The study population was geographically segregated and, together with Croatian sites, it constituted the northernmost margin of the species' distribution range. Very frequent observations highlighted a sexual tendency towards dioecy already shown by T. hirsuta in other parts of the Mediterranean coast. The flowering period lasted 10-11 months, more or less. A high proportion of female flowers and a low number of hermaphrodite flowers were recorded, in contrast with the abundance borne by the species elsewhere; gender segregation intotwo different subgroups was noted, one consisting mainly of male and protogynous plants, the second consisting basically of female and protandrous specimens.