conditions.

In the Zygnematophyceae, which share all the major enzymes for cell wall synthesis and remodifications with land plants, cell walls are composed of three layers: one outer layer consisting of mucus, a primary wall consisting of microfibrils, and an innermost layer of cellulosic microfibrils. Some species shed their primary wall and retain only the innermost layer. The cell wall may be variously decorated with striations, granules, or spines. In the