Oxalis triangularis

Native to South America from Peru to Brazil and northern Argentina, this perennial herb grows from thickened underground stems. These rhizomes bear fleshy scales that store water and nutrients, enabling the plant to regrow after periods of dormancy. Each leaf has three triangular leaflets, which fold together at night or when disturbed. The white to pale pink flowers have five petals and are borne in clusters above the leaves; they also close at night. Photographed in the department of Quindío, Colombia.