Another ID challenge....

Like last week's answer, this is also a gall - a chemically induced reaction to the presence of a causal organism by the affected plant. This particular gall is attributed to a mite called Eriophyes triradiatus (again no English name!). This mite was first recorded in Brirtain around the turn of the 19th/20th century in Essex and is formed by the distortion of the female flower buds. The reproductive organs of the tree become enlarged and many adventitious buds (those which occur where they shouldn't usually) appear. This distortion and appearance of adventitious buds forms the gall.

The galls vary in size from only about 2cm across to up to 20cm and on the continent many species of willow (salix) are affected. In the UK the most common species affected is crack willow, Salix fragilis.

The mites themselves are only about 0.1-0.2mm long, so you won't see them without a microscope(!), with worm shaped bodies and are related to spiders.

Like last week's answer, this is also a gall - a chemically induced reaction to the presence of a causal organism by the affected plant. This particular gall is attributed to a mite called Eriophyes triradiatus (again no English name!). This mite was first recorded in Brirtain around the turn of the 19th/20th century in Essex and is formed by the distortion of the female flower buds. The reproductive organs of the tree become enlarged and many adventitious buds (those which occur where they shouldn't usually) appear. This distortion and appearance of adventitious buds forms the gall.

The galls vary in size from only about 2cm across to up to 20cm and on the continent many species of willow (salix) are affected. In the UK the most common species affected is crack willow, Salix fragilis.

The mites themselves are only about 0.1-0.2mm long, so you won't see them without a microscope(!), with worm shaped bodies and are related to spiders.