[compare meiotaxyn.; perhaps compare scientific Latin Pleiotaxis, genus name (1865 or earlier)] Botanyrare the presence of more than the usual number of whorls, as in double flowers.
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1869 M. T. MastersVeg. Teratol.iii.i. ii. 353 ‘Pleiotaxy’ may be applied to those cases in which the number of whorls is increased.
1917 J. W. HarshbergerText-bk. Mycol. & Plant Pathol. xxvii. 338Pleiotaxy (Masters).—The increase in the number of whorls in a flower.