What is wasabi?

Wasabia japonica is a shrub growing in the wet and shaded gravel banks of cool mountain streams in Japan. Wasabi is member of the family of Brassicaceae and is used traditionally as a natural spice. It consists of a rhizome with bushels of large and long-stemmed, heart-shaped leaves, and of delicate white flowers which bloom in early spring. Evidence of cultivating wasabi in Japan was found as early as the Asuka era (552-710 C.E.).