Oh, so sorry I didn't happen in until this morning, wwh. What a lovely present to read about leaf-related topics! Yes, stomata I'm very familiar with and love looking very closely at leaves with a magnifying glass to see as much as I can. Botanical gardens typically have posters with cell structures greatly magnified. Would love to know a mnemonic for the photosynthesis cycle!

I think one of the most interesting leaves in terms of depth of structure is that of the Magnolia grandiflora or the Southern magnolia. Its leaves are terrifically thick, very glossly on one side as though polished in a body shop, and then thickly hairy underneath as though covered with brown felt.

Again, thanks for the information and links!