Spurious biastrepsis in Taxus baccata
Recueil des travaux botaniques néerlandais , Volume 25A - Issue 1 p. 92- 98
January 1927 Mr. P. J. Schenk, Technical Advisor 1st class of the Phytopathological Service, was so kind as to send me a dozen of branches of Taxus baccata L., in which a great deal of „big bud”1) was shown, caused by a mite known as Eriophyes psilaspis. „From these infected buds” says Mr. Schenk in an accompanying letter, commonly grow a quantity of poor sprigs, which turn about, but I am not prepared to look at the present long, strongly twisted branches as the outcome of the attack of mites. Do you think it is biastrepsis?” An examination of this abnormality, also in loco, showed in the first place that the shoots are twisted either to the right or to the left, an alternative which is also observed in the normal arrangement of the needles. Secondly it is evident from the locality of the disturbance and a transverse section of an affec .ed shoot that the abnormal branches were all of them produced in 1926 and consequently the disturbance cannot have been observed here on such a large scale till the above named year. In the third place it deserves attention that apart from the torsion the affected shoots are strongly bent and curved in an irregular way (Fig. 1 and 2). So the general aspect of this „yellowish” yewtree,.as Mr. Schenk puts it, is very abnormal. Several authorities, scientific and practical, state that they have never seen a serious disturbance like this in Taxus or some other Coniferous plant.
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