Analysis of leaf waxes as a taxonomic guide to Rhododendron subsection Taliensia

Abstract

Analysis of the hydrocarbon component of leaf waxes for a large number of specimens of Rhododendron subsection Taliensia Sleumer has shown that the distribution of n-alkanes, C(n)H(2n+2), can be a useful taxonomic feature. There is a clear distinction between taxa for which the maximum of the distribution is at C27H56 and those with a maximum at C31H64, but more subtle differences between the distributions are also evident. The extent of variation between samples from the same clone taken at different times has been estimated, and the additional variation between different specimens of the same taxon has been shown to be smaller than this. Evidence is presented to show that hybrids between C27 and C31 taxa may have a distinct alkane distribution pattern. This can be used to identify parents of some natural hybrids. The data for some taxa indicate that the present taxonomic classifications based on morphology alone are not entirely satisfactory, and provide information which may help to elucidate problems that arise within populations consisting of closely allied taxa. (C) 2000 Annals of Botany Company.