Liu, Yusheng .
Leaves of Cephalotaxus (Cephalotaxaceae, Coniferopsida) from the Paleocene of Almont, North Dakota, U.S.A.
Well-preserved and silica-permineralized leaves of Cephalotaxus (Cephalotaxaceae) from the Late Paleocene Almont flora of North Dakota provide clear adaxial and abaxial cuticular characters, which make the identification to this genus possible. The fossil probably represents a new species as it has a unique combination of foliar cuticular characters, not seen in any living and fossil members of the genus, such as wavy anticlinal walls of epidermal cells, 9-10 stomatal rows per stomatal band, more than three cells present between the two neighboring stomata within a stomatal row, and 4-6 subsidiary cells per stomatal apparatus. The fossil is the first record documented with foliar cuticular anatomy in North America and also the oldest record of Cephalotaxus as Cephalotaxus cretacea Samylina 1963 from the lower Cretaceous of Siberia has been excluded from the genus due to unrecognizable subsidiary cells. The discovery of Cephalotaxus is of significance as it will increase the diversity of the already-diverse Almont flora, especially floristic elements of gymnosperms, and it will shed light on paleoclimatic reconstruction. It is known that species of living Cephalotaxus are evergreen and highly shade tolerant, typically growing as understory trees or shrubs in humid temperate to subtropical broadleaved forests.
Log in to add this item to your schedule
1 - University of Wisconsin Stevens Point, Department of Biology, 800 Reserve Street, Stevens Point, Wisconsin, 54481, USA
Presentation Type: Poster
Location: Salon C, D & E - Gov Ballroom/Hilton
Date: Tuesday, August 16th, 2005
Time: 12:30 PM