Iris prismatica

Iris prismatica, the slender blue flag, is a plant species native to parts of the southern and eastern United States from Maine south to Alabama, as well as to the Canadian provinces of Ontario and Nova Scotia.

Iris prismatica is a perennial herb spreading by means of rhizomes that are close to the surface of the soil. Flowering stalks can reach a height of 80 cm. Leaves are long and narrow, up to 60 cm long but rarely more than 5 mm across. Flowers are pale blue to blue-violet. It tends to grow in wet conditions, and in the United States is currently state listed as threatened in Maine, New Hampshire, New York, and Tennessee, and state listed as endangered in Maryland and Pennsylvania.