Grasses can be found all over the world in all different types of climates and environments. Some have adaptations specific to their region or environment, making it possible for them to survive in the most unfavorable conditions. Grasses can be among the hardiest plants in the world, aided by adaptations that give them the edge.
Many grasses have adaptations that allow them to weather through long dry spells. Many ornamental grasses, such as those that grow native in areas like the prairies and savannas, have extremely long and complex root systems that allow them to reach water that has been absorbed into the soil and would be out of reach of shorter roots systems. The family of switch grasses can have roots that extend up to 12 feet. These grasses also tend to grow very quickly during periods of heavy rain, and can stop their growth processes during drought periods in order to conserve water and energy.
Many grasses have the ability to store water and nutrients in their roots as reserves in case the above-ground portion of the grasses get destroyed. This is a particularly common adaptation that long, ornamental prairie grasses have, as they are in an environment that is prone to wildfires. These fires will destroy the above-ground portion of the grass, which can then regrow because of the stored reserves located in its roots. These same grasses -- along with savanna grasses and salt grasses -- also have underground structures called rhizomes. These structures are used in lieu of seeds for reproduction, and new grasses will sprout directly from the rhizome. This also helps the species return after a natural or man-made disaster has decimated an area.
Much like there is a difference between freshwater and saltwater fish, grasses that live in coastal areas need to be adapted to absorb and process a different type of water. Not all grasses can thrive in saltwater conditions, but those who can have adapted ways to deal with the salt that gets absorbed through their roots. Saltgrasses often have structures on their leaves that release salt that has been extracted from the water they have absorbed. Since these areas generally have wet, sandy soils, they must also be adapted to the constant presence of water in their environment. The roots of these grasses are less susceptible to rot than other types of grasses, and can survive in the permanently wet conditions around large bodies of water.
Grasses that do produce seed have adapted to give those seeds the best chance possible of taking root and developing into new plants. If seeds are released from the parent plant when conditions are too cold, too wet or too hot for them to grow, they can remain dormant until environmental cues indicate that it's time to start growing. Some seeds remain dormant for a few months, while some can stay dormant for years before starting to germinate.