WASHINGTON — Have you ever walked past a plant and wondered whether it was safe to eat? Or poisonous? Or maybe you just liked the look of it and wondered what it was? Soon, an app might be able to tell you.

The PlantNet app is “essentially the Shazam for plants,” says Collective Evolution, and it works by using visualization software to compare your picture of a plant to the pictures in the app’s database.

So far, the project is small — just 4,100 plants in the database, and none in North America yet, out of about 400,000 species of plants in the world — but it will only grow as more people contribute photos and identifications.

The scientists behind the app say the ability to identify plants quickly will be a help to farmers who want to minimize their chemical usage, customs officials who need to identify plants being brought into their country — even expert botanists who want to track the evolution and worldwide distribution of plants.