Prickly Lettuce ( North and South Plant, Compass Plant, Milk Thistle)

• Common Name: Prickly Lettuce ( North and South Plant, Compass Plant, Milk Thistle)
• Latin Name: Lactuca serriola
• Family Name: Asteraceae/Compositae

Like its close relative, the Wild Lettuce, the sap of the Prickly Lettuce contains lactucarium, which has strong narcotic and sedative properties and is therefore not suitable for feeding to tortoises.

Prickly Lettuce is sometimes known as the North and South or Compass plant because the young upper leaves point towards North and South.  The sap contains lactucarium which is quite low in young plants but concentrates as the plant matures for flowering and can cause cardiac paralysis.  It is used as a sedative and narcotic, and the oil obtained from the seeds is used in making soap, paint and varnish.

See also Milk Thistle (Silybum marianum) which is a different plant.