Yellow sweetclover, Melilotus officinalis
I find this easy to identify by the sturdy stems, blueish-green coloring of the teardrop leaves, and spike of flowers. It can be 3′ tall in my experience.
This plant is not native, but I am including it because students seem to have some familiarity with it and because when yellow sweetclover blooms, it’s time to super up. It provides a nice long bloom time and appears before White Sweetclover.