XVI International Botanical Congess

Growth of individual gametophytes of the fern Thelypteris palustris Schott. was inspected at 12h intervals over ten or more days under continuous illumination. The growth rate oscillates with about a 36h cycle as well as expressing large fluctuations in amplitude. Experimentally produced twin gametophytes with two apical cells were found to have initially synchronous growth followed by two independent time series of cycling. The apical cell appears to be the source of oscillatory growth based on the complex growth pattern of twin gametophytes. This feature of irregular growth is taken as an example of chaos instead of system noise, again, based on the behavior of twin gametophytes.