DESCRIPTION: Appearing like a cluster of verdant volcano-like growths these tough galls can be found in loose clusters or coalesced in groups. These are easily seen on both sides of the leaf and are usually formed around the midrib. The lower surfaces have red-rimmed conical pores. The causal agent is a midge with the larvae starting white but becoming orange-red later in development. It seems that females prefer to lay their eggs on the leaves of broad-leaf willows. DISTRIBUTION: Widespread throughout Britain with some years seeing a great proliferation. HABITAT: On the leaves of various Willows.
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