PlantSnap is a plant identifying application that can recognize all kinds of plants, flowers, leaves and even mushrooms. It uses your phone's camera to capture a picture of the plant or flower in question. Afterwards, the application takes about ten seconds to analyse the picture before it gives its final verdict on the plant's name. It is not necessary that the plant will have to exist physically for the picture to be taken and the app to work. You can even take the picture of the plant from a screen and the app will still be able to give you accurate results.
Accuracy will also depend on the quality of the picture that you take and as well as your camera. On my attempt with a moderate camera, the app delivered accurate results 9 out of 10 times. It is has a fairly simple user interface and is quite engaging once you start using it.