I noticed while preparing my 2011 return that I forgot to report bank interest of less than $40. What happened was that I had two statements on the bank/brokerage website. I got the one which said 1099-MISC and I thought it included everything and didn't check the other account section.

The amount of income is LESS than $50, so you can safely ignore it. The IRS does not address such issues unless the added income is $50 or more.