https://creativecommons.org/publicdomain/zero/1.0/https://www.rawpixel.com/image/13967553Edit ImageSaveSaveEditCropCustom TextFour twigs with catkins, all from named types of poplar or aspen (Populus species). Chromolithograph by W. Dickes & co., c. 1855.Original public domain image from Wellcome CollectionMorePublic DomainFree CC0 image for Personal and Business useInfoView CC0 LicenseJPEGSmall JPEG 740 x 1200 px | 300 dpiLarge JPEG 1200 x 1946 px | 300 dpiFree DownloadFour twigs with catkins, all from named types of poplar or aspen (Populus species). Chromolithograph by W. Dickes & co., c. 1855.More