Sunday, February 26, 2012

Usnea, Herbal Medicine

Yesterday i was out cutting firewood in the swamp. One positive side effect of that is that I am usually able to find some Usnea  growing on the upper branches of maples and tamaracks. It seems to like the growing conditions in the densest parts of the swamp. I don't pass up an opportunity to collect this powerful antibiotic. Usnea barbata is the species usually found in commercial preparations. While that species does not grow here there are plenty of other species in our area. I think the one in the pic is Usnea angulata all though that is based on merely looking at photos so is probably not even close! Usnea is a lichen and it contains usnic acid which has been shown to inhibit gram-positive bacteria such as those that cause strep and pneumonia. Gram-negitive bacteria such as E.coli and salmonella are not effected by usnea. I would be reluctant to use commercial preparations of this lichen unless I was very sure of the source of material. Usnea is known to concentrate airborne heavy metals in its tissue. I want to know any that I use was collected from areas without a lot of industrial air pollution.Usnea has a slightly sweet, very, very, bitter taste.It's active principles are best extracted in a tincture with a low concentration of alcohol [ 25-30%] since most of it's compounds are water soluble. The USDA plant data base list 86 species of Usnea in North America and it grows almost every where in the world so some species may grow near you.

This is a pic of some growing on the upper limbs of a red maple. The other is on a tamarack and I am not sure if they are the same species. They look a little different to me. Wisconsin has a dozen or so species but I don't much more than I've said here. It is one area I plan to study more as there are also edible species of lichens.

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