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Proliferation of many shoots near the end of a branch in response to the death of the terminal bud

witches' broom (Wikipedia)
Not to be confused with Mistletoes, which are not the host plant's own tissue, but parasitic plants growing on the host.
For a broom associated with witches, see Besom. For the nebula, see Witch's Broom Nebula.

Witch's broom or witches' broom is a deformity in a woody plant, typically a tree, where the natural structure of the plant is changed. A dense mass of shoots grows from a single point, with the resulting structure resembling a broom or a bird's nest. It is sometimes caused by pathogens.

Witch's brooms on downy birch, caused by the fungus Taphrina betulina
Witch's broom on a white pine.
Witch's broom in Yamaska National Park, QC

Diseases with symptoms of witches' broom, caused by phytoplasmas or basidiomycetes, are economically important in a number of crop plants, including the cocoa tree Theobroma cacao, jujube (Ziziphus jujuba) and the timber tree Melia azedarach.

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