Description Back Country Vista, South Fork Boise River, ID, Flowing With NatureBalsamorhiza sagittata is a North American species of flowering plant in the sunflower tribe of the aster family known by the common name arrowleaf balsamroot. It is widespread across western Canada and much of the western United States.[2] A specimen was collected by explorer and botanist Meriwether Lewis near Lewis and Clark Pass in 1806.[3]The Boise River rises in three separate forks in the Sawtooth Range at elevations exceeding 10,000 feet (3,050 m), and is formed by the confluence of its North and Middle forks. The North Fork, 50 miles (80 km) long,[2] rises in the Sawtooth Wilderness Area, along the BoiseElmore county line, 60 miles (100 km) northeast of Boise. It flows generally southwest through the remote mountains in the Boise National Forest. The Middle Fork, approximately 52 miles (84 km) in length,[2] rises within 12 miles (19 km) of the North Fork in the southern Sawtooth Wilderness Area in northeastern Elmore County. It flows west-southwest near the town of Atlanta, joining the North Fork to form the Boise River, approximately 15 miles (24 km) southeast of Idaho City. The main stream flows southwest into Arrowrock Reservoir joining the South Fork from the Anderson Ranch Dam.Wikipedia