. Kio. 111.—Witches' broom of Silver Fir, caused by AicUUam elatinitm. (v. Tuteiif phot.) that the sliDOt produced from such a bud no longer retains its normal direction of growth, Itut becomes negatively geotropic, like an independent plant. This marked negative geotropism is characteristic of all witches' l)rooms (Fig. 16), and shows clearly that they are no longer controlled by the same laws of grcnvth as the n(jrmal lateral branches. They have in addition other peculiarities not e\hil)ited l)y normal plants. Thus tlie witches' broom of the silver Hr causetl by iiiyccliiini ot Aa-uliuni di(
. Kio. 111.—Witches' broom of Silver Fir, caused by AicUUam elatinitm. (v. Tuteiif phot.) that the sliDOt produced from such a bud no longer retains its normal direction of growth, Itut becomes negatively geotropic, like an independent plant. This marked negative geotropism is characteristic of all witches' l)rooms (Fig. 16), and shows clearly that they are no longer controlled by the same laws of grcnvth as the n(jrmal lateral branches. They have in addition other peculiarities not e\hil)ited l)y normal plants. Thus tlie witches' broom of the silver Hr causetl by iiiyccliiini ot Aa-uliuni di(tiiiiiiii is not evergreen, but bears needles whieh fall each autumn. Moreover, no witches' broom Itears (lowers or I'liiit; for example, that on the cherry (Fig. 5) ]) exclusively leaf-buds which unfnjil siiiiultaneousjy with ttie
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Photo credit: © The Bookworm Collection / Alamy / Afripics
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectparasit, bookyear1897
