Zynga and American Express have launched Zynga Serve Rewards Program. This will take the form of the ‘Serve Money Tree’ that will grow with every transaction; FarmVille users that to sign up and make real world purchases of $25 or more (up to 5 purchases a month) to see the Tree grow.

“We’re excited to partner with American Express to invent new ways for people to experience Zynga play in more parts of their day,” said Mark Pincus CEO and Founder of Zynga. “Together we can add surprise and delight to everyday shopping.”

“We’re thrilled to expand our relationship with Zynga and provide an easy way for players to earn Zynga virtual game cash by learning about Serve and signing up to receive the many benefits of our digital wallet,” said Dan Schulman, president of Enterprise Growth, American Express. “As the commerce landscape continues to change, and online and offline spending converges, Serve is focused on partnering with companies like Zynga to create unique value for our customers in the environments they love.”