US plants of Lake Huron tansy are ssp. huronense. Subspecies bipinnatum grows in Alaska and the Yukon. Plants in CA, OR, and WA were once included in this species, but are now separated as T. comphoratum. It's fun to find patches of these unusual flowers along the upper Michigan and Wisconsin shores. Tansies are very aromatic, and this species does not disappoint. If you ever get to the Great Lake shores in July or August, these are worth looking for and not hard to find. If not, just sniff a garden tansy leaf, close your eyes, and imagine the view. These plants fit many of the criteria for use as medicine, but I have found no references to that.