How to determine the source of the Web To Lead form

We have generated two Web to Lead forms. One is for scheduling product demos and another is for requesting an account on our service. We are a small company and all leads are assigned to one lead owner at the moment. When I click Approve Leads, I see a list of all the leads and there doesn't seem to be a way to differentiate the source form from where the lead details were submitted.

Is there any feature that helps sort these leads based on source of lead data submission?