Smithsonian Learning Lab has uploaded a set of postcards created by the Digitization Program Office (DPO). Each state and the District of Columbia is represented by a herbarium sheet of a plant collected in that state. The postcards are available at http://learninglab.si.edu/q/ll-c/oMrY7y1Wdt46GRwC. These were made possible through the herbarium digitization project done at the National Museum of Natural History in partnership between the museum and the DPO. As of March 2020, the U.S. National Herbarium has digitized 3.7 million plant specimens, which are free to view and download from the Botany Collections webpage.
The Maryland postcard, represented by the state flower Black-Eyed-Susan (Rudbeckia hirta), is just one of 51 postcards made by the Smithsonian Digitization Program Office (DPO). Each postcard features a specimen from each state of the USA and the District of Columbia. The specimens were digitized as part of the Herbarium Digitization Project by DPO and the National Museum of Natural History.