Definition of Williamsonia
: a genus (the type of the family Williamsoniaceae) of fossil cycads having slender more or less branched stems and conspicuous bracts or scales associated with the fructification and occurring in rocks from the Upper Triassic to Middle Cretaceous in both the New and Old Worlds
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Origin and Etymology of williamsonia
New Latin, from William C. Williamson †1895 English naturalist + New Latin -ia
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