The true grass family, Poacae, is one of the most abundant and widely distributed botanical groups. Found on every continent except Antarctica, they dominate habitats such as salt marshes, steppes, savannas, and more. Where they rein, they tend to create vast biomes. In fact, if continuous areas of grassland habitats are tallied, the result would show that grasses cover more than 30 percent of the dry land on Earth!
Although sedges resemble true grasses in many ways, they are different enough to warrant a family of their own, Cyperaceae. As noted in the rhyme at top of this category, sedges "have edges"; seen in cross section, a sedge stem is triangular, not round. and while the leaves of a sedge plant do look quite grasslike, they are arranged in ranks of three, as opposed to the two alternating leaves of true grasses.