Wiesen-Bärenklau
In 1970, Nielsen extracted 8-methoxypsoralen from four species of the genus "Heracleum" in the carrot family Apiaceae, including "Heracleum mantegazzianum" and "Heracleum sphondylium". An additional 32 species of the genus "Heracleum" were found to contain 5-methoxypsoralen (bergapten) or other furanocoumarins.