For anatomical and morphogenetical investigations, parts of S. officinale were fixed and stored
in 70% ethanol. Shoot vascular anatomy was investigated in two plants, one from each of the
collection sites. For light microscope observations, the whole main stem of flowering aboveground
shoots was cut with a hand razor into serial cross sections. Selected sections were stained
using traditional methods of phloroglucin test for lignin (Barykina et al. 2004) and drawn. The
drawings were used for reconstruction of three-dimensional shoot vascular structure. Images of
the sections were taken using MDC200 camera combined with MBS-10 dissecting microscope
and saved using ScopePhoto application.