tuberoid

/ˈtubəˌrɔɪd/
adjective
  1. Resembling a tuber (a swollen underground stem or root) in shape or appearance.
    • The gardener noticed a tuberoid growth on the old tree's roots.
    • The plant had a tuberoid root system that stored water during droughts.
    • Some potatoes have a tuberoid shape that makes them easy to peel.