A century of seed ferns: A symposium to celebrate paradigm shifts in the understanding of seed plant
Krings, Michael , Klavins, Sharon D. , Serbet, Rudolph , Taylor, Thomas N. , Taylor, Edith L. .
Seed fern morphology and structure: new insights on Glenopteris and Odontopteris from the late Paleozoic North America.
Compression fossils contribute greatly to our understanding of the morphology, biology, and ecology of seed ferns. Here we present new results on two particularly interesting but insufficiently understood compression seed fern taxa from the upper Paleozoic of the midwestern United States: the late Early Permian Glenopteris splendens Sellards from Kansas and the Late Pennsylvanian Odontopteris brardii (Brongniart) Sternberg from Missouri. Frond morphology and epidermal anatomy of G. splendens are described from the Wellington Formation (Cimarronian) in central Kansas. Certain features are interpreted as adaptations to seasonal aridity and elevated soil and ground water salinity. Pachymorphous (succulent) pinnules may represent a modification to water stress, because succulent foliage delivers large quantities of storage water. Succulence is also effective as an adaptation to elevated salinity since storage of large quantities of water increases the salt accumulation capacity of the fronds. Peg-like idiocuticular projections into/between the epidermal anticlinal cell walls may also represent an adaptation to aridity; in extant plants, heavily cutinized anticlinal walls are often associated with a xeromorphous epidermis. Specimens of Odontopteris brardii from the Bonner Springs Shale (Missourian) of western Missouri indicate that fronds were bipinnate. This seems to contradict the widely accepted opinion that O. brardii is conspecific with Odontopteris minor f. zeilleri Potonié, because fronds of the latter taxon are asymmetrically tripinnate. We suggest that heteroblastic development occurred in O. brardii / O. minor f. zeilleri, and bipinnate fronds were produced by young plants, although intraspecific differences in frond architecture may also represent mechanisms of adaptation.
1 - Bayerische Staatssammlung für Paläontologie und Geologie, Richard-Wagner-Strasse 10, Munich, D-80333, Germany
2 - University of Kansas, Dept. of Ecology and Evolutionary Biology, 1200 Sunnyside Avenue, Lawrence, Kansas, 66045-7534, U.S.A.
3 - University of Kansas, Natural History Museum, 1345 Jayhawk Blvd., Lawrence, Kansas, 66045-7561, U.S.A.
Presentation Type: Symposium
Location: Ballroom 1 (Cliff Lodge)
Date: Tuesday, August 3rd, 2004
Time: 10:30 AM