What are the characteristics of Pinnularia?
Pinnularia are elongated elliptical unicellular organisms. Their cell walls are composed chiefly of pectic substances on a rigid silica framework. Their walls are composed of two halves called thecae (or less formally, valves.) These halves overlap like a Petri dish and its cover. What is raphe Pinnularia? The raphe is wedge shaped in transverse section….