Approximately 145 million: That’s the number of specimens – including plants, animals, minerals and human artifacts – curators estimate are held in the Smithsonian National Museum of Natural History. However, these estimates do not reflect the billions of tiny individual specimens contained on microscope slides – thin pieces of glass that fix objects in place for observation – each representing a record of a species at a specific place and time.

Microscope slide collections are an underused part of natural history collections because they are small, fragile and generally not well cataloged. One slide is usually recorded as a single specimen, even though it may contain hundreds of thousands of identifiable samples. They play a significant role in documenting life both present and past, and they are also a core educational resource for training future scientists.

Our team of plant paleontologists and evolutionary biologists use microscopy techniques to extract the full potential of natural history collections. In our recently published research in the journal PLoS One, we developed a way to digitally image whole microscope slides and make the specimens they contain available to scientists and students around the world.

Unseen troves of specimens

The Denver Pollen Collection contains about 70,000 slides of fossilized pollen extracted from rocks of many geological ages. The collection, now housed at the Smithsonian National Museum of Natural History, represents........

© The Conversation