Hardt's sequoia (Sequoia hardtii)

Redwood Coast Redwood
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Sequoia hardtii - Extinct Redwood Species | Botanical Encyclopedia

Preserved in Cenozoic sedimentary formations, the extinct conifer Sequoia hardtii reflects the widespread distribution of the genus across Europe prior to the Pleistocene glaciations. This species thrived in warm-temperate, humid forests that spanned the European continent during the Miocene epoch.

Its fossilized remains have been recovered from numerous coal deposits and clay pits, providing key evidence of ancient European forestry. The species represents a crucial link in tracing the phytogeographical migration of redwoods.

Taxonomy

  • ∟ царство Plantae
  • ∟ division Tracheophytes (Vascular Plants)
  • ∟ subdivision Spermatophytes (Seed plants)
  • ∟ superclass Gymnospermae (Gymnosperms)
  • ∟ division Pinophyta
  • ∟ subclass Cupressidae
  • ∟ order Cupressales (Cypresses and junipers)
  • ∟ family Cupressaceae (Cypress Family)
  • ∟ subfamily Sequoioideae (Sequoias)
  • ∟ genus Sequoia (Coast redwood)
  • ∟ species Sequoia hardtii (Hardt's sequoia)

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Morphology

Diagnostic features of this species are primarily derived from fossilized leafy shoots and female cones. The needles are linear-lanceolate, slightly curved, and attached to the stem with a decurrent base.

Specific anatomical features include:

  • Foliage orientation: Needles are distichously arranged on the branchlets, showing a flat, two-ranked appearance.
  • Stomatal bands: Microscopic analysis reveals parallel rows of stomata on the abaxial surface of the leaf cuticle.
  • Seed cones: The female cones are relatively small, globose, and composed of numerous peltate scales.

Applications

Fossil remains of this taxon are widely utilized in paleoecological modeling to determine past humidity and temperature regimes in Europe. The presence of these fossils indicates a humid, subtropical to warm-temperate paleoclimate.

The fossilized wood and foliage also provide valuable data for studying the evolution of wood decay fungi. They help scientists understand the co-evolutionary history of conifers and their associated pathogens.

Interesting facts

Fossils of this redwood are frequently found associated with ancient brown coal (lignite) deposits in Germany. They contributed significantly to the biomass that eventually formed these extensive European coal seams.

The species co-existed with diverse warm-temperate flora, including ancient oaks, maples, and swamp cypresses. Its extinction in Europe was ultimately driven by the cooling and drying trends of the Pliocene and Pleistocene ice ages.

Geography of distribution

  • Germany
  • Croácia

Sources

  • Global Biodiversity Information Facility (GBIF): Sequoia hardtii (https://www.gbif.org/species/41019884)
  • The World Flora Online (WFO): Sequoia (http://www.worldfloraonline.org)
  • Paleobiology Database (PBDB): Sequoia hardtii (https://paleobiodb.org)

See also

Coast Redwood

Coast Redwood

Sequoia sempervirens

The coast redwood (Sequoia sempervirens) is a massive conifer native to coastal California and Oregon. …

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True Araucarias

True Araucarias

Araucaria sect. Araucaria

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