Pollination flow in hybrid formation between Orchis morio and Orchis papilionacea (Orchidaceae) in two different habitats

Two geographically separated natural populations of Orchis x genndarii, a h ybrid between Orchis morio and Orchis papilionacea, were examined to establ ish the parental lineages using nuclear ribosomal DNA and chloroplast DNA l ength polymorphisms. Results indicate that O. morio more frequently provide s the maternal lineage in the population from the volcano Mount Vesuvius (c entral Campania, Italy) than in the one from Cilento (southern Campania, It aly); in the latter locality maternal genomes are preferentially provided b y O. papilionacea. The possible causes of this difference in reproductive b ehavior are discussed in the light of the pollination biology of parental s pecies and of environmental influences.