rootstock
/ˈruːtstɒk/noun
1- a rhizome根状茎。
1.1
- a plant on to which another variety is grafted根砧木, 根接植物。
1.2
- a primary form or source from which offshoots have arisen原始形态; 根源：
the rootstock of all post-Triassic ammonites.
所有后三叠纪菊石的原始形态。