It was early May in the Kickapoo Valley when the photographer came upon violet wood-sorrel in bloom in the oak woods. He found it in the sort of place in which it usually grows - the acid soil where black oaks and pignut hickories and yellow star grass are found, a sour soil to support a sour plant. For the word Oxalis means sour, because of the acidulous leaves and the watery, acid stem.
Oxalis violacea L.
April - May. Oak woods, dry slopes.
To the hiker, the sorrels are peculiarly pleasant to find on a warm day in spring. The leaves and stems as well as the tight green pods of seeds are all acid to the taste and are almost as refreshing as a glass of fresh spring water. The three-parted shamrock leaves often have been used in salads, but should be used sparingly because of the oxalic acid which they contain, and which is not good when taken in too great a quantity.
The violet wood-sorrel has five-parted, lavender-rose flowers on slender, smooth, purplish stems, usually several flowers to a stem. All the leaves and flower stalks spring separately from the hairy little brown corm from which slender roots go down into the dry soil. This is unlike the yellow sorrels which have branching stems. The leaves of Oxalis vio-lacea are silvery green with red blotches on each of the heart-shaped leaflets. They are sensitive to changing hours of daylight and fold themselves together at sundown, to remain so until the increasing light rays of dawn open them wide again.