Oregon wood sorrel and Oxalis oregona are native to the Pacific Northwest.
The Wood Sorrel family includes the common yellow wood sorrel.There are small trees and small herbs in this family.Other plants in the family include a common houseplant and a violet wood sorrel.The family is mostly found in warm climates.
This perennial herb has a long tap root and can grow on the ground or in the air.Stems can grow up to 9 inches tall, but they are usually shorter.Stems can be smooth or hairy.The leaves are palmately compound and look like clover leaves.The leaflets are folded along the midvein.There are 2 to 2.5 centimeters of leaves.There are clusters of yellow flowers at the end of long stalks, which hold the flowers above the leaves.The flowers are yellow with five petals.The capsule is 2 to 2.5 centimeters long.The capsules are upright.The capsule when ripe opens and throws tiny brown seeds up to a meter or more away.The seeds of this species have ridges on them.
There are a variety of habitats for the common yellow wood sorrel.It can be difficult to grow.It is reported from all of the contiguous United States except for Oregon, California, Nevada, and Utah.It is reported from Newfoundland Labrador to British Columbia.
Depending on the part of the country in which it is found, this species may flower throughout the year.Most of the time it flowers spring to fall.The flowers are visited by bees, ants and butterflies.The leaves open and close during the day.The plant has a sharp taste.People who use leaves in salads may be at risk of having stones.