A searchable database of 13,000 associated diatom records and the Harvard Herbaria Type Specimen Catalog. You can search the type specimens or full collection. Also has the collections of the New York Botanical Garden and Princeton College. A great searchable database containing descriptions of thousands of extinct plants. Patterns of migration and evolution through geological time can be clearly examined to help better understand the history of climatic and environmental change.
Several collections are here.
The Linnean Herbarium is in Swedish. Type specimen collections for the Scandinavian and Regnell Herbaria and more. Separate searchable databases for ferns, flowering plants, mosses, hepatics and lichens, and algae.