Salix nigra

Salix nigra, commonly known as the black willow, is a tree species native to eastern North America. It is present from Nova Scotia and southern Ontario, west to Nebraska and southeastern Arizona and south to Florida and northeastern Mexico. The largest American species of willow, it is typically found along streams and in swamps, hence it is also known as the swamp willow (not to be confused with Salix myrtilloides). Goodding's willow (Salix gooddingii) is sometimes considered a variety of the black willow, which would extend its range to western North America.

Description
It is a small to medium-sized deciduous tree, growing to 20-30 m in good conditions, exceptionally up to 40 m. It has long, thin leaves, 7-13 cm long and 1-2 cm broad, dark, shiny green color, with a lighter green underside. It is dioecious, with small, green flowers that are borne on catkins 2.5-7.5 cm long. The fruit is a 5 mm capsule which splits open when mature to release the numerous minute, down-covered seeds.

Uses
Black Willow roots are very bitter, and have been used as a substitute for quinine in the past.