what class is fern sori
The Class of true ferns was once named Polypodiopsida (now Filicopsida) and the Order Polypodiales contains most fern families. The basic fern structure is thus taxonomically defined by the Polypody, a once-divided or one-cut fern; the individual pinna are broadly connected at the base to the central stem, or rachis.The Polypody grows from a woody underground stem called a rhizome that extends horizontally along the ground.he basic fern structure is thus taxonomically defined by the Polypody, a once-divided or one-cut fern; the individual pinna are broadly connected at the base to the central stem, or rachis. The Polypody grows from a woody underground stem called a rhizome that extends horizontally along the ground.