Blackthorn : Prunus spinosa
Plant : Blackthorn can be an important early season forage for bees. It belongs to the Rosaceae family. These thorny spiny shrubs grow up to 4 m and can be covered in small white blossom early in the season, before its leaves emerge. The fruit produced by this tree is known as the sloe berry. Its habitat includes hedgerows and margins of woodland.
Flower : Blackthorn flowers between March and May. The flower is up to 30 mm in diameter and has 5 white petals, as well as 5 sepals. It has several stamen, with long filaments. The ovary is superior.
Pollen : The pollen load of the blackthorn is a burgundy colour. The grain is round, has three furrow type pores around the equator and is approximately 38 um in diameter. The surface is generally smooth, with some pitting. The exine is thin.
Rex Sawyer’s book, Pollen Identification for beekeepers is really helpful for understanding the features of pollen. In Bob Maurer’s book, Practical Microscopy for Beekeepers, he shows some simple techniques for making up pollen slides. Click here to return to plants for bees index.