Morphological fruit types of basal angiosperms in the flora of Ukraine

Basal angiosperms is a paraphyletic group of plants before branching eudicots and monocots. This group of angiosperms is of great scientific interest because it is the most ancient representative of the flowering plants retained for today. In Ukraine, both ANA-grade and magnoliids are presented. The species diversity of basal angiosperms is about half a percent of the flora of vascular plants of Ukraine, which caused a low research activity on this subject. The objectives of the present study were to elucidate the morphological diversity of fruits within basal angiosperms inhabiting Ukraine and estimate their evolutionary level and adaptations. The morphological diversity of fruit, according to our concept, comprises the structure of the gynoecium, ovary insertion, placentation, ovule number (pre-anthetic features), as well as principal fruit type and morphological adaptations for dispersal (post-anthetic features). The principal fruit types were distinguished according to the principles established previously for classifying fruits of monocots and rosids of the flora of Ukraine. Within the basal angiosperms of the flora of Ukraine, four principal fruit types were established: aggregate fruit, capsule, berry, and one-seeded fruit. Among them, the aggregate fruits are the most numerous. In Nymphaeaceae and Aristolochiaceae, which belong to the native flora of Ukraine, fruits are syncarpous, multi-seeded and inferior, while in the families cultivated in Ukraine (Annonaceae, Magnoliaceae, Calycanthaceae, Schisandraceae, and Lauraceae) fruits are apocarpous, superior and often have low seed number in a carpel. Each family has peculiar gynoecium and fruit features, which can be advanced as well as ancestral. In this article, the carpological spectrum was created to reveal the distribution of principal fruit types in families, genera, and species of the basal angiosperms of the flora of Ukraine. In these spectra, aggregate fruits are the most numerous; however, they occur in families of cultivated flora only. Most species have adaptation for dispersal by animals (birds or ants). The conclusion was made that in the native flora of Ukraine, the most derived members of basal angiosperms are retained.