What is a Tuber?
A tuber is a starchy underground storage organ. Some gesneriads have tubers which can get quite large, up to four to five inches in diameter. Tuberous gesneriads are often grown with the top third of the tuber above the soil line, making for an unusual presentation. Tuberous gesneriads generally have a dormant period and resprout after a short period of time. Tuberous gesneriads are found only in South America and are considered New World gesneriads.
