Mercury
Mercurialis annua (Annual Mercury), Mercurialis perennis (Dog's Mercury)
Familie:
Euphorbiaceae, Spurge family
Where to find this herb :
Dog's Mercury: moist, shadowy in deciduous forests. Annual Mercury: open, cultivated ground, next to roads.
Part(s) used:
whole herb
Special constituents:
methylamine, trimethylamine, hermidine
Correspondance:
14 (Culpeper)
Use:
addition to amulets
Bingelkruid 
Bingelurt The two species of Mercury are quite similar, but grows in different places. You can also tell them apart thus: Annual Mercury has a branced stem, Dog's Mercury has a single, upright stem.
Mercury is dioecious, that is, you get female and male plants. The fruits are small, hairy balls, looking much like the male testes. This used to cause a certain misunderstanding, as even learned men in ancient times mistook the female plants for male! Indeed, the "male" plants were recommended to women wishing to give birth to a son, the "female" recommended if she wanted a daughter. The herb was, in addition, recommended against all kinds of women troubles - one example was to rub it on "the secret parts" during birth, to ease the process.
The herb's name refers, of course, to Mercury. Not everyone agrees with this, though. Culpeper writes: "Mercury, they say, owns the herb, but I rather think it is Venus's, and I am partly confident in it too, for I never heard that Mercury ever minded women's business so much; I believe he minds his study more."
Druehyld writes, that this herb "makes all herb mixtures exquisite".
The herbs is slightly toxic and as far as I could find out no longer used in medicine. Animals eating large amount of Mercury produces a discolored, red urine caused by hermidine oxidating to chrysohermidine. Maybe this color caused the herb to be attributed to Mercury.