Lignotuber /(lĭg`nō*to͡o"bẽr)/

Lig·no·tu·ber

Lignotuber

n.
  1. A woody swelling on a tree or shrub, usually contained entirely below or just above the surface of the ground, and having buds which enable the plant to survive cutting or a fire that destroys the portion of the plant above ground. After such damage to the plant, sprouting commences from the lignotuber. (Bot.)