Ferns use their leaves for both reproduction and carbon fixation. How do they manage to use one organ to tackle two very different jobs?
Far from being a simple process, reproduction can be a complex and costly venture. Obtaining the proper balance between reproduction, growth, and maintenance can lead to compromises in form and function. In the case of flowering plants, sexual reproduction is largely constrained to highly specialized flowers and fruits, focusing reproductive efforts in one organ.
Ferns pose a unique set of challenges as they use the leaf as the site of both reproduction and carbon fixation. Britton and Watkins examine two cases of extreme foliar dimorphism in ferns and find that fertile-sterile dimorphy comes at considerable carbon costs to ferns likely influencing species ecology. A potential benefit of such costs is increased spore dispersal distance and more fine-tuned control over frond phenology.