Danthonia compressa, commonly known as Mountain Oatgrass, Flattened Oatgrass, or Slender Oatgrass, is a perennial bunchgrass that is native to a variety of habitats including open woodlands, grassy meadows, and rocky outcrops in eastern North America. It is found in eastern Canada and the Eastern United States, with a particular affinity for the high-elevation environments of the Appalachian Mountains in the southern part of its range. This grass typically grows up to 31 inches long and may exhibit a decumbent growth habit, with most leaves concentrated at the stem bases. The inflorescence is a panicle bearing up to 17 spikelets, which are notable for their delicate appearance during the flowering season.

Mountain Oatgrass is valued for its adaptability to various soil types and its ability to thrive in both full sun and partial shade. It is often used in restoration projects, native plant gardens, and as a component of wildflower meadows due to its low maintenance requirements and contribution to biodiversity. It reproduces by seed and can also sprout new stems from basal buds, allowing for vegetative spread. While generally disease-resistant, it can be susceptible to rust in some conditions. It is not known for aggressive roots or significant invasiveness issues.CC BY-SA 4.0