https://creativecommons.org/publicdomain/zero/1.0/https://www.rawpixel.com/image/13959347Edit ImageSaveSaveEditCropCustom TextTwo plants, holy thistle (Silybum marianum) and Canada thistle (Cirsium arvense): flowering and fruiting stems. Coloured etching by C. Pierre, c. 1865, after P. Naudin.Original public domain image from Wellcome CollectionMorePublic DomainFree CC0 image for Personal and Business useInfoView CC0 LicenseJPEGSmall JPEG 803 x 1200 px | 300 dpiLarge JPEG 1440 x 2151 px | 300 dpiFree DownloadTwo plants, holy thistle (Silybum marianum) and Canada thistle (Cirsium arvense): flowering and fruiting stems. Coloured etching by C. Pierre, c. 1865, after P. Naudin.More