ibclogo XVI International Botanical Congess


Abstract Number: 4824
Poster No. = 729


MORACEAE WOODS FROM THE OLIGOCENE OF BAJA CALIFORNIA SUR, MEXICO.


Martínez-Cabrera, Israel (1) Cevallos Ferriz, R.S. (2).., (2) Instituto de Geología, UNAM. México.


Three wood samples from the Oligocene El Cien Formation, Baja California Sur, Mexico, have abundant paratracheal parenchyma, high proportion of solitary vessel elements with simple perforation plates, and large vessel element-radial parenchyma pits, characteristic of Moraceae. Among the two samples related to Maclura, one has sheath cells and is ring porous, supporting its recognition as a member of section Maclura, while the lack of these characters suggest that the second sample is closer to section Chlorophora. The family has been postulated as originated in Gondwane, but the presence of these taxa in Mexico, and the Eocene fossil record of Ficus in Eurasia end North America suggest that the genera may have originated in Laurasia. The similar extant distribution of these genera also suggest that both had similar migration routes. Further documentation of these genera in Laurasia will help to document the northern origin of some common tropical taxa of extant low latitude North America, as well as their long history in this area.


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