Coenocyte

A coenocyte (from Greek: κοινός (koinós) = "common" + κύτος (kýtos) = "box, i.e. cell") is a multinucleate cell which can result from multiple nuclear divisions without their accompanying cytokinesis, in contrast to a syncytium, which results from cellular aggregation followed by dissolution of the cell membranes inside the mass. The word syncytium in animal embryology is used to refer to the coenocytic blastoderm of invertebrates.

Coenocytic cells are present in diverse and unrelated groups of algae, including Xanthophyceae (e.g., Vaucheria), red algae (e.g., Griffithsia) and green algae (e.g., the internodal cells of Chara).

In the siphonous green algae Bryopsidales and some Dasycladales the entire thallus is a single multinucleate cell, which can be many meters across (e.g. Caulerpa). However, in some cases, crosswalls may occur during reproduction.

The green algal order Cladophorales is characterized by siphonocladous organization, i.e., the thalli are composed of many coenocytic cells.

In contrast to the Cladophorales where nuclei are organized in regularly spaced cytoplasmic domains, the cytoplasm of Bryopsidales exhibits streaming, enabling transportation of organelles, transcripts and nutrients across the plant.

Diplomonads, like Giardia, have two nuclei.

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