Mostly heterogametic (morphologically differentiated gametangia):
–Hypha-like antheridia
•Attracted to oogonium by hormones and develop fertilization tubes
–Large, globose oogonia
•One or more oospores in oogonium
•Simultaneous meiotic divisions occur in antheridia and oogonia prior to fertilization
•Karyogamy occurs in oosphere to form oospore that matures inside oogonium