Perhaps the truest sign of an App Store that really does encompass everything possible is when an app as original and as clever as Leafsnap comes along. It's an app that even far from green fingered me can appreciate.
At its most basic, Leafsnap is an electric field guide developed as a joint effort by researches from Columbia University, the University of Maryland and the Smithsonian Institution. It offers many, many high-resolution images of leaves, flowers, petiole (that's the stalk of a leaf to the uninformed), seeds, bark and fruit. Leafsnap also includes all the trees of New York City and Washington D.C with the trees of the entire of the United States to follow. It's a great compendium in its own right, especially for free.
Its most intriguing feature however comes in the form of the visual recognition software side of things. This recognition system enables users to take photos of various leaves so that the app can identify the tree species involved. It does need a little work. It presumably only works in the USA for now for understandable reasons considering its origins. Users are also required to have a white background in order to distinguish a leaf. Botany enthusiasts would do well to pack a sheet of paper with them on their excursions, but the potential is fantastic.
GPS functionality means that users can share this data and the location in which they found the tree with others, ultimately allowing for scientists to use the data for their research and see just how such greenery is doing across the country.
It's complicated stuff and at least for now, it all requires a Wi-Fi connection to work but it's also a free app that could shine a glimpse of the future for botanists.
Green fingered iOS devices would do well to check out Leafsnap which is available now.