Wood sorrel (Oxalis sp. ) leaves. Numbering about 800 species, Oxalis is found growing on woodland floors throughout temperate regions of Eurasia. It has clover-like, three-part compound leaves, made up of heart-shaped leaflets. It is grown as both an ornamental plant and for its leaves, which are used in salads. The best known wood sorrel is the shamrock, which is associated with Saint Patrick and is the emblem of Eire.