There are almost 400,000 known species of plants in the world with many more getting discovered each year. These plants are categorized through phylogenetics, a system which categorizes plants and other organisms based on their relationships with each other. There are currently 64 orders and 420 families of plants on Earth. These plants and their relationships to each other can be seen here through Flowering Plant Systematics. Grasses are a diverse group of plants belonging to the Poales order and Poaceae family that contains over 12,000 species. Many of these grasses are used for food, fuel, fiber, and yes lawns! Did you know that just 3 species of grasses (wheat, corn, and rice) provide 60 percent of the total plant calories that humans consume worldwide? Wheat, one of the oldest cultivated food crops, can be traced to Egypt as many as 10,000 years ago. Futhermore, many of the world’s most productive farmlands evolved under native grass cover due to its fibrous root system and high carbon sequestration capacity.
There around 10 to 12 species of grasses primarily used for home lawns. While they each differ in their various strengths that make them ideal for a particular use, they also share many common features. One of the most easily observed of these features is their low growth habit and ability to tolerate mowing.
Many grasses tolerate mowing because of the position of their growing point at the top of an un-elongated stem called the crown (Figure 1). This is a region of actively dividing cell tissue that results in the growth of turfgrass leaves, which occurs near the soil surface. As long as vegetative growth continues, newly formed leaves will continue to be formed at the crown and will replace older leaf tissues as they are mowed off of the plant.
As these leaves emerge, they form into two parts; the blade and the sheath. The blade is the unfolded or unrolled part of the leaf while the sheath is the lower portion of the leaf, which attaches it to the rest of the turfgrass plant.
Many fescues and ryegrasses have a bunch-type growth habit while Buffalograss, Creeping bentgrass, St. Augustinegrass, and Centipedegrass have stoloniferous growth habits, and Kentucky bluegrass and some species of Fine fescue have a rhizomatous growth habit. Bermudagrass, Seashore paspalum and Zoysiagrass have both rhizomes and stolons, which is one of the features that often make them hardy in high-traffic settings.