A new pteropsid fructification from the middle pennsylvanian of kansas usa
Palaeontology 19(2): 307-315
Discovery of a well-preserved, fertile frond segment in Middle Pennsylvanian petrifaction material from Kansas [USA] provides the basis for description of an annulate pteropsid fructification [NORWOODIA angustum gen. et sp. nov.]. Numerous sporangia are attached to the abaxial surface of laminar pinnules in either a solitary fashion or in groups of 2-6. Individual sporangia range up to 240 .times. 320 .mu.m and are divided into a narrow stalk and a spheroid distal region. Sporangial walls are 1 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, 16-20 .mu.m and exhibit a prominent trilete mark. Little or no wall ornamentation is present. Fructifications of this type suggest the presence of leptosporangiate, possibly filicalean, ferns during Pennsylvanian time.