The leaves do vary quite a bit, presumably depending on environmental conditions and/or genetics. There is so much variability within and between species, that there is currently a lot of confusion about exactly how many species of Melilotus there are, with various taxonomists either splitting M. officinalis, M. albus, M. arvensis, and M. luteus or lumping them together.
All that being said, without the flowers, the only sure thing about the plant in Lee Ann's pictures is that it is a legume.
