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Current status of the Progymnospermopsida
(Elsevier, 1976-01)
The three progymnosperm orders, Aneurophytales, Protopityales, and Archaeopteridales, are characterized and analyzed. The possibility that some of the apparent taxonomic diversity of the Aneurophytales and Archaeopteridales ...
The primary vascular system of Callixylon
(Elsevier, 1979-08)
The primary vascular system of Callixylon (main stem axes of Archaeopteris) is composed of a discontinous cylinder of longitudinal bundles from some of which traces diverge radially in a regular, helical pattern. Tangential ...