Latin name: Oxalis tuberosa
Plant Family:  Wood Sorrel (Oxalidaceae)
Lifespan: Perennial
Origin: Andean foothills (Chile)
Growing: Loves full sun and overwinters in the Pacific Northwest really well with a deep mulch layer (~3").
Edibility: The young leaves have a citrus flavor and are delicious both raw or cooked. The tubers are smaller than, but very similar to potatioes and are the most consumed part of this plant. The stalks are also used as a rhubarb substitute. 
Medicinal uses: None that is known.
Permaculture Uses: It's a great groundcover to shade out weeds and hold moisture in the ground. Also serves as great habitat for beneficial insects.
Price: $10 per plant