the entire plant

Flowering period: June to September.

From Cook's Physiological Dispensatory, 1869

Properties and Uses:  The root of this plant is relaxant and very moderately stimulant, and expends its chief power upon the kidneys.  By its use, the amount of watery discharge in the urine is greatly increased; and at the same time a soothing impression made upon the mucous membranes of the renal apparatus.