You probably only have to ask on a relevant forum here if anyone has an image of the particular plant or plant part you are looking for and that you can use, as in Jay's offer above, since it's for non-profit. Unless
@dave has a problem with that that I haven't thought of. That would be less time consuming than going through the database and then hoping the photographer of what you choose will answer your Tree Mail.
I have stumbled on quite a few wrongly named plants in stock photo collections. Not infrequently, for example, are true lilies (Lilium) labeled daylily (Hemerocallis). I think errors like that would be caught pretty quickly here.
