Caudiciform

Pachypodium namaquensis is also known as "Elephant Trunk," or "Namaqua thick-foot." It is native to the Richtersveldt desert, in Namibia. 

Ficus palmeri originates from Mexico, and can grow large large interesting trunks and roots when grown in a container. Ficus Palmeri has large green leaves with light green veins. Makes for a gret bonsai specimen.

Dioscorea elephantipes is slow growing plant with a unique above ground tuber. It grows a climbing stem with heart shaped leaves. Leaves and vines will fall off as plant goes dormant.