Three flowering plants: a garden dahlia (Dahlia cultivar), a calamint (Calamintha coccinea) and a verbena (Verbena tweediana). Coloured engraving by J. & J. Parkin.

Licence: Public Domain Mark

Credit: Three flowering plants: a garden dahlia (Dahlia cultivar), a calamint (Calamintha coccinea) and a verbena (Verbena tweediana). Coloured engraving by J. & J. Parkin. Wellcome Collection. Source: Wellcome Collection.