SynopsisCork and cork‐formation in taproot and crown of the alfalfa plant were examined. The cork formation arises from a dividing phellogen cell in the pericycle. Initial periderm develops during the first year of plant growth after primary elongation is completed. Disease or injury may upset the pattern. New cork cambium was found beneath decaying tissues. Death of tissue may also be attributed to natural death of previous year's stem. These dead areas do not prevent growth of new tissues on the crown but probably weakens the plant for stress periods.