Thank you Sir. I have already accepted
Medicago lupulina in my earlier mail. The second species is very confusing. I am also not sure if it can be
Trigonella corniculata or a
Melilotus indicus. I titled this post, based on distribution in Bengal Plants, without going into detail. But since these are found in cultivated field, distribution is irrelevant here. I also regret that I thought all is one species at different developmental stage.
Now, since the leaflets of the 2nd species in question have less than 7 pairs of lateral veins and petioles are as long as or exceeding leaflets I think it may be Trigonella corniculata L.
Regards
surajit