Barb says I'm didactic, so here goes. . .
Parallel evolution is a phrase as much misused as used, and I got it wrong on the wildflower page. Parallel is when two evolutionary branches if an organism remain similar, as with elephants and mastodons. But when branches from different species become alike, it is convergent evolution. With absinthium and sage, we have converging species from different familes, mint and aster, that have developed the same aroma. In other regards, they are still quite different. Absinthium is successful enough that it is listed as a noxious weed in some places.