Celandine
Chelidonium majus
Synonyms:
Swallow-Wort
Family:
Papaveraceae, Poppy family
Where to find this herb:
It is quite common; find it in a shady spot in your own garden
Special constituents:
several isoquinoline alkaloids: sanguinarine, chelidonine, chelerythrine, berberine and coptisisine
Correspondance:
Sun/Fire (Cunningham); Sun (Beyerl, Culpeper)
Uses:
For amulets; gives protection and lifts the spirit. Medicinally: vulnerary
Stinkende Gouwe 
Svaleurt Celandine is easy to recognize because of its bright orange sap. Be careful, the sap can cause allergic reactions. According to Aristoteles the swallows use the sap to cure inflammation of the eyes in its young ones. Thus the name, Chelidonium, which means swallow. Do not attempt to copy this alleged behaviour! The sap is no good for eyes, at least not human ones - but it does have some effect on warts.
Celandine is used in homeopathy as a treatment of liver cancer; a study using mice shows the drug has a significant effect (1).
The alchemists called the herb "the gift of heaven" because it was said to include all the elements, and thus could be used to create the Philosopher's Stone. The correspondance is the Sun - in spite of the fact that this herb grows in the shadow! But it carries the Sun within it :-)
Magically, Celandine is protective. It is also good against mood swings. It helps you, in times of crisis and conflict, to make the right decisions and act upon them. If you feel restrained in relationships, carry an amulet with Celandine.
Once you have Celandine in the garden, it sheds its seeds willingly and can become quite evasive, at least in the shady parts.
1) Surjyo Jyoti Biswas and Anisur Rahman Khuda-Bukhsh: Effect of a homeopathic drug, Chelidonium, in amelioration of p-DAB induced hepatocarcinogenesis in mice. BMC Complementary and Alternative Medicine 2002 2:4