Brittany Connell, via email
I found this double-headed gerbera on one stem. Is this a common occurrence?
Jennifer Stackhouse says
This looks to me like fasciation, as there are two stems fused below the double flower. It is probable that the damage was done when the tiny buds were just developing within the plant. Fasciation is caused by an external factor, such as mites or even herbicide, which damages the growing point in the apical meristem. It is unlikely the plant itself has any permanent damage, and the double flower head will probably not occur again.