The origin of Oxalis corniculata L

Area of Science:

• Botany
• Ethnobotany
• Archaeobotany

Background:

• Oxalis corniculata L. is a globally distributed weed with an uncertain origin.
• Despite its placement in a South American section of the genus, evidence for a South American origin is weak.

Purpose of the Study:

• To investigate the origin of Oxalis corniculata.
• To review historical and archaeobotanical evidence.
• To summarize ethnobotanical literature on its medicinal uses.

Main Methods:

• Review of herbarium specimens.
• Analysis of historical literature.
• Examination of archaeobotanical findings.
• Summary of ethnobotanical records.

Main Results:

• No strong evidence supports a European origin before the 15th century or a North/South American origin before the 19th century.
• Direct archaeobotanical evidence indicates Oxalis corniculata existed in Southeast Asia over 5,000 years ago.
• Historical and archaeobotanical data suggest its presence in Polynesia predates European exploration.
• Traditional medicinal use is most widespread in Southeast Asia, suggesting a long human association.

Conclusions:

• Southeast Asia is the most probable origin of Oxalis corniculata.
• This aligns with the circum-Pacific distribution of the Oxalis section Corniculatae.
• The species likely spread to Europe and Polynesia via ancient trade routes.