BLACKBERRY FLOWERS

The blackberry is an edible fruit produced by many species in the genus Rubus in the family Rosaceae, hybrids among these species within the subgenus Rubus, and hybrids between the subgenera Rubus and Idaeobatus. The taxonomy of the blackberries has historically been confused because of hybridization and apomixis, so that species have often been grouped together and called species aggregates. For example, the entire subgenus Rubus has been called the Rubus fruticosus aggregate, although the species R. fruticosus is considered a synonym of R. plicatus.

The flowers are produced in late spring and early summer on short racemes on the tips of the flowering laterals. Each flower is about 2–3 cm in diameter with five white or pale pink petals. The drupelets only develop around ovules that are fertilised by the male gamete from a pollen grain. The most likely cause of undeveloped ovules is inadequate pollinator visits. Even a small change in conditions, such as a rainy day or a day too hot for bees to work after early morning, can reduce the number of bee visits to the flower, thus reducing the quality of the fruit. Incomplete drupelet development can also be a symptom of exhausted reserves in the plant's roots or infection with a virus such as raspberry bushy dwarf virus.

This post is part of the Floral Friday Fotos meme.