Leaves of McDonough grass are divided into three different sectors, the sheath, the blade, and the collar region.  The sheath is the portion of the leaf that encases the shoot or stem until is is mature enough to emerge.  The blade is the long and slender piece that grows horizontally away from the main shoot.  The area located on the back side of the plant where the sheath and the leaf come together is known as the collar region.  This region is used to differentiate between grass plant species.  The key function of the leaves of McDonough grass is to convert enery from sunlight into chemical energy that the grass plant can use as food.  Chlorophyll is the molecule found in the leaves that uses energy from the sun to turn water and carbon dioxide into sugar and oxygen.  This method of converting energy is known as photosythesis.