The leguminosae family is the third largest plant family in the world, containing over 730 genera; some of which are quite interesting
Members of the legume family have a symbiotic relationship with specific microorganisms that colonize little bb bullet sized nodules on the root of the plant. These microorganisms intake atmospheric Nitrogen and exchange this with the plants supply of starches, while the legume plant consumes the nitrogen; once the plant dies or is choped and dropped, it adds organic nitrogen rich biomass to the soil, making legumes extremely important in any type of natural gardening.
Legume flowers are generally very simliar and noticable, while also being a quick way for a partial ID, typically. White clover, which im sure most of us are familiar with, has little white balls of many of these similiar and noticable flowers. The flowers almost have like a toungue. After you observe an average legume flower enough, you will start to see very similiar flowers everywhere!
Another easy and noticable quick tip to legume ID is the seed pods. Legumes very often produce and contain their seed inside of pods.
However, possibly the best way to ID a legume is to look to see if the plant has any BB root nodules growing, on its roots.
All of these are great tips i have gathered ime
Pic 1, 2, and 3: average legume flowers
Pic 4: average legume seed pod
Pic 5: legume root nodules
I hope this helps to IDing and growing native legumes throughout your garden and food forest