Sepal

A sepal is a seperate part of the flower forming the calyx. It is usually green. This is used to protect the flower bud. There are usually the same number of sepals as their are petals. In the following picture, you can see some of the sepals on the upper stem and their also are some on the underside of the petals, but they aren't very visible.

Source: Sepal. (October 3, 2005). biology-online.org. Retrieved on September 5, 2011, from
http://www.biology-online.org/dictionary/Sepal