Givetian Stage

What happens during this time?

• Ibyka, an iridopterid, appears during this time

  • The whorled habit of the lower axes and anatomy suggests a possible connection to the horsetail lineage

• Stumps of Eospermatopteris (Pseudosporochnales) appear in sediments along water edges

  • First tree-like plants on Earth with mostly primary growth, and radially aligned cells that are suggestive of wood production

• Cladoxylopsid Panxia from South China, similar to the Laurussian Pseudosporochnales and Rotoxylon in anatomy

• The aneurophytes (progymnosperms) are on the landscape as large woody vines, growing among the larger cladoxylopsid trees

  • These plants are the oldest evidence of true secondary xylem, or woody growth in plants

• Runcaria heinzelinii, a proto-seed or precursor of seeds appears around 385 Ma (Gerrienne 2004)

  • Runcaria may represent an intermediate between the spore-bearing and seed-bearing habit

  • Others include Granditetrasporites zharkovae (Arkhangelskaya and Turnau, 2003 ) and Spermasporites allenii (Marshal & Hemsley 2003))