lignotuber
Concise Oxford English Dictionary © 2008 Oxford University Press:
lignotuber /ˈlɪgnəʊˌtjuːbə/
▶noun Botany a rounded woody growth at or below ground level on some shrubs and trees that grow in areas subject to fire or drought, containing a mass of buds and food reserves.
'lignotuber' also found in these Oxford entries:

