Article: A new pteropsid fructification from the Middle Pennsylvanian of Kansas
Discovery of a well-preserved, fertile frond segment in Middle Pennsylvanian petrifaction material from Kansas provides the basis for description of an annulate pteropsid fructification. Numerous sporangia are attached to the abaxial surface of laminar pinnules in cither a solitary fashion or in groups of from two to six. Individual sporangia range up to 240 x 320 um and are divided into a narrow stalk and a spheroid distal region. Sporangial walls are one cell layer thick. Cells over much of the sporangium exhibit thick walls and represent a massive annulus. Thin-walled sporangial cells occur as a narrow, vertically oriented zone. Spores are radial, 16-30 um and exhibit a prominent trilete mark. Little or no wall ornamentation is present. Fructifications of this type suggest the presence of leplosporangiale, possibly filicalean, ferns during Pennsylvanian time.