Tree ID: Now on your iPhone

Can't tell a beech from a birch? There's an app for that. Last month, scientists from Columbia University, the University of Maryland, and the Smithsonian released Leafsnap, a free iPhone and iPad app that promises a simple way to identify Northeastern U.S. tree species from their leaves.

Unlike other field guides -- even digital ones -- Leafsnap doesn't rely on users picking from a list of characteristics to puzzle out which species they're looking at. Instead, it relies on visual recognition technology -- a kind of software that's also used to identify faces, and has been advancing rapidly in recent years -- to match a photo of a leaf taken in the field with species in Leafsnap's database.

On Leafsnap's website, its creators say it will be the first in a series of iPhone-ready field guides. (The New York Flora Association blog asks if the graminoids are next. Somehow we doubt it. But there's always the Peterson's guide.)

Botanically-minded Watershed Post readers: If you've got an iPhone, and are tempted to give this a spin, drop us a line and let us know how it performs in the field. You can download it free from the Apple Store here.