Givetian Stage

What happens during this time?

• An iridopterid, Ibyka †, appears during this time

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

• The cladoxylopsid Panxia † from South China, similar to the Laurussian Pseudosporochnales and Rotoxylon † in anatomy

  • Stumps of Eospermatopteris † (pseudosporochnids) appear in sediments along water edges. These are the first tree-like plants on Earth with mostly primary growth, and radially aligned cells that are suggestive of wood production

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

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

• A para-seed plant (or precursor of seeds), Runcaria heinzelinii †, appears around 385 Ma (Gerrienne, 2004)

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

  • Megaspore "seeds" are also found, including Granditetrasporites zharkovae † (Arkhangelskaya & Turnau, 2003) and Spermasporites allenii † (Marshal & Hemsley, 2003)