Sample selection and herbarium label interpretations
A total of 155 herbarium specimens of Mentha subgen.Mentha were obtained from the herbaria at Lund University, Sweden
(LD), Uppsala University, Sweden (UPS), and Oskarshamn, Sweden (OHN);
Table S1. Specimens were selected based on the plant identification by
the collector(s) and/or subsequent re-identifications by botanists, with
the aim to include the taxa, M. longifolia , M. suaveolens ,M. spicata , and the hybrid M. × rotundifolia(M. longifolia × suaveolens ). However, many specimens were
re-identified based on the result of our morphometric analyses (see
below). From here on, the taxon names M. longifolia (L.) L.,M. suaveolens Ehrh., M. spicata L. and M. capensisThunb. (and their hybrids) are used to denote those groups of specimens
identified by the morphometric analyses that most closely correspond to
the morphological descriptions of these species in standard floras
(Stace, 1993; Tutin, 2010). However, it should be stressed that these
morphologically defined groups may not exactly correspond to the
biological species that previous authors have referred to by these
names, nor to their nomenclatural types. All specimens were
morphologically evaluated and a subset of 93 samples were whole genome
sequenced.