Willow is a challenging plant to taxonomically identify on the species level. There is constant cross-breeding and nomenclature can be a challenge. Most of the willow that we see in the high country is bushy in stature and usually nestled next to streams and bodies of water. A source of food for wildlife and a source of medicine for people in the form of acetyl-salicylic acid (aspirin), willow has been used traditionally as an anodyne (pain reliever) and analgesic, anti-inflammatory plant for many generations.
This plant, like Yarrow (Achillea millefolium) is one that is handy for backcountry medicine and first aid. Boiling the bark from the young parts of the plant can extract antiseptic chemical constituents that can be applied locally as a poultice. For an infected wound, a tea (for external application) can be made by using the boiled bark (over 30 minutes in a covered pot) along with a Tablespoon of boric acid per pint of water. This tea can be used as a wash as well.
Useful molecules include glycosides populin and salicin as well as tannins. Willow is known for decreasing inflammation. Tea for drinking internally is another route of administration and can be helpful as an analgesic for the urinary tract (i.e. bladder, urethra). The willow can help cool and quench inflammation and infection like the cool water that provides habitat for this pain plant.