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OVULE INVERSION IN THE EARLIEST CONIFERS
Author(s) -
Mapes Gene
Publication year - 1987
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/j.1537-2197.1987.tb08734.x
Subject(s) - ovule , biology , sensu , paleozoic , paleontology , botany , pollen , inversion (geology) , paleobotany , strobilus , evolutionary biology , plant development , genus , genetics , tectonics , gene
Recent investigations of ovulate conifer cones from southern Europe and midcontinent North America have independently documented that certain Paleozoic walchians have inverted ovules, rather than the erect ovules previously thought to characterize the most primitive conifers. Reinvestigation and consideration of other walchian conifers, including Moyliostrobus and Lebachia piniformis (sensu Florin), reveals that they also had inverted ovules. These different patterns of ovule orientation demonstrate that the nature and the polarity of the character states are dramatically different than popularly believed, and the shift from megasporophyll to ovuliferous cone‐scale occurred within the Paleozoic walchians.