A common question is are plant identification apps any good and which is best? I’ve recommended iNaturalist as it has a helpful community and knowledgeable humans helping with identification. But correspondence in People & Nature from Michael Rzanny and colleagues suggests that the machines are incredibly close to humans in accuracy. They looked at 842 photos of plants that experts had already identified, testing them with a free app called Flora Incognita. The results showed that the app could correctly name plants 98.8% of the time – far better than previously thought. It opens the possibility of rescanning herbaria for errors.
The team used photos that had already been identified by professional botanists as their test material. Three plant experts double-checked cases where the app’s identification didn’t match the original label. For particularly tricky plants, like the genus Alchemilla, they consulted additional specialists. Of the 842 photos, Flora Incognita was definitely right for 819 species, and definitely wrong for eight. For the remaining 14, experts couldn’t be sure the app was wrong.
Previous studies had shown plant ID apps to be less accurate, with the best apps getting about 87% of identifications correct. The increase in accuracy could have two big contributors. First, the apps could be getting better. Second, Rzanny and colleagues found that different apps use different plant names, which can make it seem like they’re wrong when they’re actually correct, they’re just using old synonyms. However, the striking accuracy does not make humans irrelevant yet. The authors note the reliance on photos as a weak point.
A botanist, identifying plants in the field, utilizes various approaches simultaneously, including keys, diagnostic characters and implicit knowledge… On the contrary, a single picture presented to an identification app only offers a limited two-dimensional perspective of some of the plant’s attributes. Images may or may not clearly depict important plant parts and structures, and many of the additional sources of information (odour, location, soil properties, surrounding plant community, season) are not available for the identification process.
Rzanny, M., Bebber, A., Wittich, H. C., Fritz, A., Boho, D., Mäder, P., & Wäldchen, J. (2024). More than rapid identification—Free plant identification apps can also be highly accurate. People and Nature. https://doi.org/10.1002/pan3.10676 (OA)
