Green Carpet Of Common Yellow Woodsorrel (Oxalis Stricta) With Yellow Flowers : (pix Sanjiv Shukla) Stock Photo

Common yellow woodsorrel (Oxalis stricta), also called yellow woodsorrel, common yellow oxalis, upright yellow-sorrel, lemon clover, or more ambiguously and informally "sourgrass", "sheep weed", or "pickle plant", is a herbaceous plant native to North America, parts of Eurasia. This plant tends to grow in woodlands, meadows, and in disturbed areas as both a perennial and annual. Erect when young, it later becomes decumbent as it lies down, and branches regularly. Commonly considered a weed of gardens, fields, and lawns, it grows in full sun or shade. The alternate leaves of this plant are divided into three heart-shaped leaflets, which curl up at night and open in the day to perform photosynthesis.