Anthecology of gynodioecious species Ranunculus acris (Ranunculaceae) in Moscow region

Abstract

Background. Ranunculus acris L. (Meadow Buttercup) is a perennial herbaceous short-rhizome polycarpic plant. Mentions of flowering and pollination characteristics in gynodioecious R. acris are scarcely found in the literature. Materials and methods. Observations were made in the natural conditions of the Moscow region from 2021 to 2023 by generally accepted methods. Results. Perfect flowers are weakly protandric, bloom for 5–6 days and pistillate flowers – for 3–4 days. The opening of flowers in a closed thyrsus and its lateral dichasia with different reduction options occur according to the order of branching of the shoot. The total flowering time of perfects and females varies from 3 to 4 weeks, and depends on weather conditions. R. acris is an obligate xenogamous species: the pollen/ovary ratio is from 4594 to 7149 in perfect flowers. Both types of flowers open synchronously, with a maximum at 10 a.m. Conclusions. Efficient cross-pollination in R. acris is reached by the presence of gynodioecy, the synchronous rhythm of perfect and female flowering, the formation of a large number of pollen grains in both types of flowers, later onset and earlier completion of flowering of females, and by gametophyte self-incompatibility.

Keywords

• ranunculus acris
• gynodioecy
• anthecology