Ryegrass is a cool season grass that is often used in lawns and sporting fields.

Cool season grasses start growth at 41 °F, and grow at their fastest rate when temperatures are between 50-77 °F, in climates that have relatively mild/cool summers, with two periods of rapid growth in the spring and fall. They retain their color well in extreme cold and typicaly grow very dense, carpetlike lawns with relatively little thatch.

Bent grass or Bentgrass is a cool seasonal grass. Bent grass is a desirable grass for golf course tees, fairways and greens and high traffic lawns.  

Cool season grasses start growth at 41 °F, and grow at their fastest rate when temperatures are between 50-77 °F, in climates that have relatively mild/cool summers, with two periods of rapid growth in the spring and fall. They retain their color well in extreme cold and typicaly grow very dense, carpetlike lawns with relatively little thatch.

Colonial Bentgrass, a relatively low maintenance turf grass. 

Bluegrass is also know as Smooth Meadow-grass.  Bluegrass is native to Europe, Asia and northern Africa. Bluegrasses are cool seasonal grasses.

There are thousands of varieties of lawngrass.   Each type of lawn grass is adapted to specific conditions of precipitation, temperature, and sun/shade tolerance.

Breeders are constantly creating new and improved varieties of the base list of lawngrass species.

The two basic categories are cool season grasses and warm season grasses.