I was walking through Chiwaukee Prairie with a very knowledgeable friend, who knows her prairie plants better than I do. (picture that, she's scary smart) We were using both iNaturalist and Picture This side by side. The best performer was iNaturalist.
The iNaturalist was inaccurate only on a couple of plants. We also used Picture This and it was VERY WRONG quite a number of times. iNaturalist has a much higher accuracy rate and it includes a lot of distribution data that Picture This does not.
Nothing beats taking a few good images with your Android or other phone, then in the evening sitting with an ounce or two of 10 year old bourbon, neat, paging through various guides, and botanical keys, with Netflix movie on in the background.
But if one is not comfortable with using botanical keys, and or does not have plant guide books, or Botanical Flora's, I suppose iNaturalist and other identifier programs can help get you started. Just remember these programs are NOT very accurate. The better programs are maybe 80% accurate. They are better at getting to the right genus, but if there are multiple species in the same genus chances are quite high the app will get the species wrong.
Take good pictures. Note the attachment of the leaves to the stems (alternate, opposite, whorls, etc) Get a shot of twigs bark and dormant buds. Bud photos should show the pattern of the scales protecting the dormant bud. If flowers are present photos face on, side and back of flowers. Especially in Aster and Sunflower family the side view and back view of the flower is more important in figuring out identity than the face on view of the flower.
If your ears are not delicate, if you are able to hear the occasional curse without fainting, there is a really fun You Tube channel run by "Tony Santoro" - "Crime Pays, but Botany Doesn't" Tony talks like a street kid raised in the Italian-American neighborhood around Taylor Street before 1975, or "Back of da Yards", or one of the South Side Italian neighborhoods. Tony massacre's pronunciation of botanical terms, deliberately, just for fun, but he uses the terms correctly. His oldest vids started in the greater Chicago area, and it seems he occasionally adds vids when he is visiting relatives here. He lives in the Berkley-Oakland area of California, and his botanizing is mainly in the southwestern deserts of the USA. He has some very useful tutorials on using botanical keys and how to identify virtually any plant you stumble across. He was an engineer for a railroad. I believe much of his botanizing was done during forced breaks while driving a freight train from Oakland California to somewhere in Texas. Every so many hours he was required to take a break, much like truck drivers, and he'd park his train, then take a walk around the scrublands where ever he ended up.
He has since stopped working for the rail road, and just makes botany vids full time. His best stuff is Southwestern USA deserts. His trip to Australia and trip to New Caledonia are interesting. His trip to Oaxaca, Mexico includes a cameo of a very very rare Cypripedium orchid. But check his YouTube vids out, especially the tutorials on how to identify a plant you are not familiar with.
