Verbascum chaixii Vill. (Eur., W-As.) – A very rare and ephemeral alien. There are but three Belgian records: first seen in 1912 in Vilvoorde (without further details), subsequently in Jette (Brussel). Apparently last seen on debris in Kessel-Lo (Blauwput) in 1951 (as the very different Verbascum blattaria).
Verbascum chaixii is possibly overlooked in Belgium. It is a garden ornamental that is much reminiscent of native Verbascum nigrum. All recent claims, however, were erroneous and ascribable to hybrids of the latter, especially with Verbascum densiflorum and thapsus. Such plants are sterile (no seeds produced), filament hairs are paler purplish (often some whitish), leaves are hairier, etc.
Verbascum chaixii itself is a variable species. All Belgian collections have leaf margins that are crenate but not lobed. Such plants belong with subsp. austriacum (Schott ex Roemer & Schultes) Hayek (syn.: V. austriacum Schott ex Roemer & Schultes).