Year after year in early spring fields in Menorca are stained in a deep yellow color.
The reason for this metamorphoses is the Vinagrella (Oxalis pes-caprae), a fully invasive plant, originally from South Africa, that first arrived on the island between the 1700's, probably introduced by British colonists as ornamental flowering plant, or livestock feed although some believe that it arrived to the island accidentally in citrus trade between Menorca and the continent.
Today it has become an uncontrollable plant that can be found almost anywhere. It has a reputation for being very difficult to eliminate once it has spread over an area of land.
The plant has been used in various ways as a source of oxalic acid, as
food, and in folk medicine. The raw bulbs have been used to deal with
tapeworm and possibly other worms. The plant has also been used as a
diuretic, possibly hazardously, in the light of observations in the
following section. The lateral underground runners, which tend to be
fleshy, have been eaten raw or boiled and served with milk. The golden petals can be used to produce a yellow dye.