|Bigtooth aspen from|
It's called LeafSnap, it's free, and it was downloaded over 150,000 times in its first month. The creators are currently working on including all the trees in northeast US, then adding western US trees--and then they're seeking something like tree-id world domination by expanding around the globe.
LeafSnap searches images collected by the Smithsonian Institution, and returns info on the tree's bark, flowers, seeds, and fruit. And get this: it uses facial recognition technology to recognize the leaves. And when a user snaps those pics, the resulting tree identifications are sent automatically to a database that uses mapping information from the phone to determine the tree's location. This info can later be used to monitor tree populations.
To continue the amazingness, similar apps might be developed to identify fish and butterflies or other insects.
For more info, check out what Ecotrope and The Seattle Times have to say. And what do you say--would you use Leafsnap?