Salix Nigra, commonly known as Black Willow, is a species of willow tree native to North America. It is a deciduous tree with dark brown to black bark and long, narrow leaves. There are several synonyms for Salix Nigra, including Salix Purpurea, Salix Caprea, and Salix Vitellina. These synonyms refer to different varieties of the willow tree found in different parts of the world. Regardless of the variety, willow trees are known for their medicinal properties, and have been used for centuries to alleviate pain and inflammation. They are also commonly used in landscaping and erosion control, and their wood is used to make furniture and other products.