We did this http://www.luontoportti.com/suomi/en/ a couple of years ago. It is based on an elimination process – you describe what you see and the application narrows down on the options. Works very well in practice, and can be applied to all sorts of indentification purposes in the wild, such as fish, birds and butterflies.

We also gave the image regocnition path a thought but it seemed to be quite a tall order. Hopefully they come up with a novel approach on this!