QUINCY, IL--(Marketwire - Apr 21, 2011) - Mercantile Bancorp, Inc. (NYSE Amex: MBR) (the "Company") today announced it has merged its majority-owned subsidiary, Mid-America Bancorp, Inc., into the Company. Prior to the merger, Mid-America was the sole shareholder of Heartland Bank, headquartered in Leawood, Kansas.