Abstract
The pattern of mitotic activity is related to form in the small coenocytic green alga (Blastophysa rhizopus Reinke. Mitoses occur as a wave pattern within single nonspheroidal coenocytes, whereas within single spheroidal coenocytes, nuclear divisions are completely synchronous. The waves are uni- or bidirectional, depending on the region of mitotic wave initiation. Factors which may be influenced by the external micro-environment of different coenocytic forms are suggested as possible mitotic initiators.