 The coralloid root system is a symbiosis of the cycad's roots and cyanobacteria of the genera "Nostoc" and "Calothrix".In "M. riedlei" the nitrogen (N2) capture is most active in wet seasons and nitrogen content is doubled within 8–11 years.Examination of the response to recent burns found the weight ratio of coralloid roots to the bole increased and the concentration of nitrogen at the roots was higher, suggesting nitrogen fixation met the need of rapid leaf regrowth that occurs after these events.