There is a short section below the terminal blade where the stipe is bare. They can be ellipsoid to subpherical, and may be tuberculated. Figure redrawn by Stephanie Frei from Friedland and Denny, 1995. Sporophylls - specialized blades that house the reproductive sori. These are typically smaller and darker than the sterile blades.
New lamina can also grow adventitiously along the rachis.
Differentiation of Tissue Meristoderm - this is the outer layer and grows to increase girth. Medulla - the innermost layer, the medulla is made up of hyphal cells and specialized sieve elements that facilitate the flow of fluids. Morphological Variation Morphological differences between plants is generally based on geography. From Los Angeles to the southern limit of Baja California, individuals generally have smooth stipes and wrinkled sporophylls.