Floral Morphology and Phenology Traits of Sambucus australis Cham. & Schltdl. Growing Spontaneously on the Buenos Aires Waterfront

The southern elderberry (Sambucus australis Cham. & Schltdl.), whose berries have highlighted functional properties, is native to temperate regions of eastern South America and is found growing spontaneously at the Reserva Ecológica Costanera Sur (RECS) in Buenos Aires, Argentina. This study aimed to describe the development of the flower bud to ripe fruit of S. australis in the agro-ecological conditions of the RECS, evaluate the different floral phases in relation to climatic factors, and identify the visiting insects that could act as potential pollinators. Flowers have all the organs to classify them as hermaphrodites; functionally, some flowers have shortly stamens without pollen and others have a non-functional ovule. Male and female flowers exhibited substantial synchronization, with the appearance of button flowers and anthesis phases occurring either simultaneously or very closely. On the other hand, it adapts to climatic changes that may occur by modifying the dates of the start of flowering and the maximum expression of the anthesis phase. Rainfall significantly influenced the opening of flower buds, the number of flowers in anthesis, and the harvest of the fruits of this species. Visiting insects which could perform pollination have been identified.