Format: ORAL

Constantin I. Fomichev1,2, Maxim S. Nuraliev1,3, Nikolay A. Vislobokov1,3, Leonid V. Averyanov4, Margarita V. Remizowa1

1 Lomonosov Moscow State University, Moscow, Russia 2 Shenzhen MSU–BIT University, Shenzhen, China 3 Joint Russian-Vietnamese Tropical Scientific and Technological Centre, Hanoi, Vietnam 4 Komarov Botanical Institute, Saint Petersburg, Russia

Peliosanthes is one of Southeast Asian genera of Asparagaceae (Asparagales). Species of Peliosanthes(Asparagaceae) are common herbs in tropical and subtropical evergreen forests. We studied inflorescence morphology, flower structure and flower anatomy, with special emphasis on its vascular system, in 13 species of Peliosanthes. We revealed raceme and thyrse as two distinct inflorescence types in Peliosanthes. Probably, thyrse evolved several times from a raceme in the evolution of the genus, which appeared to be available due to the presence of bracteoles (floral prophylls). A characteristic feature of Peliosanthes is the presence of an androecial corona, i.e. a tube formed by congenitally fused stamens. The corona is absent from the closely related genera of Asparagaceae and therefore can be considered as a synapomorphy of Peliosanthes. Our data show that the ovary position (superior, semi-inferior and inferior) is not associated with any differences in the structure of the gynoecium but is a consequence of the different shapes of the ovary roof. According to our results, species differ in the presence of septal nectaries: nectaries are absent from P. longicoronata and P. triandra, and therefore these species lack an asymplicate gynoecium zone, and their style is formed by a symplicate zone. In the other species, the nectaries are located in the hemisymplicate zone, and the style is formed by the asymplicate zone. The flower vasculature in all the studied species is fundamentally uniform; the interspecific differences are only found in the levels of bundle separation. The structure of the ventral carpel bundles correlates with the presence or absence of the septal nectaries. Our data supplement the phylogenetic findings providing additional evidence for the distinctness of species and lineages within Peliosanthes, and also they fulfill the gaps in knowledge on its basic flower structure.