Caudiciform
Caudiciform plants are those that form a caudex—a thickened, swollen stem, trunk, or aboveground roots. The term caudiciform doesn't apply to any particular genera or family but rather a growth adaptation within species as a response to a specific environment. There are over 100 genera of plants that contain species classified as caudiciforms.
These plants can look like a mere potato when dormant (Stephania) or a huge sculptural elephant foot when mature (Dioscorea elephantipes). Caudiciforms have the remarkable ability to store energy in their fat stems which allows them to withstand long periods of dryness