rhizome
noun /ˈraɪzəʊm/
/ˈraɪzəʊm/
(specialist)- the thick stem of some plants, such as iris and mint, that grows along or under the ground and has roots and stems growing from itWord Originmid 19th cent.: from Greek rhizōma, from rhizousthai ‘take root’, based on rhiza ‘root’.