Volatile components variation in the Teucrium marum complex (Lamiaceae) from the Balearic Islands

The volatile compounds of 18 samples from the western Balearic Islands belo nging to three taxa of the Teucrium marum L. complex (T. marum subsp. marum , T. marum subsp. occidentale and T. marum subsp. drosocalyx) were fraction ated by distillation-extraction and analysed by means of GC-MS. Seventeen c omponents were characterized and the quantitative data were subjected to mu ltivariate and clustering techniques. Two main groups appeared, one compris ing T. marum subsp. occidentale samples and the other grouping T. marum sub sp. marum and T. marum subsp. drosocalyx accessions. Chemical data and taxo nomic groupings generally agreed, but quantitative and qualitative differen ces within and between taxa were found. Specimens from Minorca and Cabrera islands showing intermediate morphological features between T. marum subsp. marum and T. marum subsp. occidentale were included within the T. marum su bsp. marum-T. marum subsp. drosocalyx group in the Principal Component Anal ysis. The origin of these intermediate specimens is discussed, and it is su ggested that they are local variants of T. marum subsp. marum which had an independent origin throughout its area. (C) 2000 The Linnean Society of Lon don.