Oxalis articulata, known as pink-sorrel, pink wood sorrel, windowbox wood-sorrel, sourgrass, Netho (khatta) saag (India) is a perennial plant species in the genus Oxalis native to temperate South America. It has been introduced in Europe in gardens and is now naturalized in these areas.
As the name would imply, this variety of Oxalis typically has pink to violet flowers with petals 10–15 mm long. This species has "Plants arising from a thick, woody, irregularly nodulate-segmented rhizome often with persistent, thickened, and lignescent petiole bases; flowers 3–12 in umbelliform cymes, less commonly in irregular cymes". The plant is a perennial and typically grows up to 45 cm tall and 2 cm in diameter. Spreads by rhizomes (up to 15 cm) to form colonies. It is hermaphrodite and also infrequently produces seeds in long, cylindrical capsules.
Give credit where credit is due: Wikipedia 2019