The Paleobotanical Laboratory of the National Museum of Nature and Science (NMNS) in Ibaraki, Japan, hosts an extensive collection of more than 4000 cleared leaves made of plants from around the world. Cleared leaves are an excellent resource for studying leaf venation and morphology, which makes them a useful comparative tool for many paleobotanists. The NMNS collections contain leaves of angiosperms as well as rare gymnosperms and pteridophytes. Images of this incredible collection are now available online.
You can search the NMNS Cleared Leaf Database here.