Boucher, Lisa .
A novel angiosperm reproductive structure from the Late Cretaceous of New Mexico.
Macrofloras from the Fruitland-Kirtland Formations of northwestern New Mexico are not only valuable for paleoecological studies, but intensive sampling has yielded several types of reproductive structures that may be useful for phylogenetic studies. Specimens deposited in this late Campanian floodplain preserve a significant record of angiosperms radiating into floodplain subenvironments previously dominated by conifers. In this study, over twenty specimens of an inflorescence were examined using light and scanning electron microscopy. The compressions are preserved at several different sites having a fine clay matrix, and associated aquatic remains indicate that the plant grew in or near low energy environments. The inflorescence is determinate and less than 2 cm in diameter. It is attached to a straight, robust peduncle greater than 2 cm in length and 1.5-3 mm wide. The convex receptacle is globose to elliptical. The flowers are unisexual with distinct carpels up to 2 mm in length, which are numerous and appear to be reflexed. The carpels are surrounded by numerous staminodia or tepals that are 4-5 mm in length. Based on the available suite of characters, this inflorescence most closely identifies with several orders in the basal eudicots. The implications of this affiliation will be discussed.
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1 - University of Nebraska-Omaha, Department of Biology, 6001 Dodge St., Omaha, NE, 68182-0040, USA
Presentation Type: Oral Paper:Papers for Sections
Location: Lake Erie/Hilton
Date: Tuesday, July 10th, 2007
Time: 11:15 AM