Most of these cyanotypes are from Bertha E. Jacques’s work. Those images—of milkweed, dandelions, lavender, and dog fennel—are taken from the public domain images made available by the Smithsonian American Art Museum. More information can be viewed at https://americanart.si.edu/artist/bertha-e-jaques-2441

Some of the others are by Anna Atkins and Anne Dixon for their 1853 book, Cyanotypes of British and Foreign Ferns. The Getty Museum has digitized their copy and placed the images in the public domain; it can be viewed in full at http://www.getty.edu/art/collection/objects/32412/anna-atkins-and-anne-dixon-cyanotypes-of-british-and-foreign-ferns-photographic-title-page-british-1853/