Caytoniales

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Caytoniales
Temporal range: Mesozoic
Scientific classification
Domain: Eukaryota
(unranked): Archaeplastida
Kingdom: Plantae
Superdivision: Spermatophyta
Order: Caytoniales

The Caytoniales is an extinct order of seed plants whose presence is recorded in fossils collected throughout the Mesozoic Era (around 250 to 70 million years ago).[1][2][3] The plants are part of the group called seed ferns because they are seed-bearing plants with fern-like leaves.[3]

The first fossils to be identified in this order were discovered in a Middle Jurassic formation in Yorkshire. The plants are believed to have grown in wetlands of some nature and may have been small trees. They are considered a gymnosperm by many botanical authorities, but were once thought to have an evolutionary relationship with the angiosperms, or flowering plants, because their seeds are born in a partially enclosed cupule (a modified leaf with reproductive organs).[1] The leaves are palmately compound with 3-6 leaflets 2-6cm in length.[3] The pollen grains are winged, like those of gymnosperms, and the pollen is bisaccate like the pollen of pine trees.[3][4]

Form taxa[edit]

  • Sagenopteris -- leaves
  • Caytonanthus -- microsporophyll, or pollen producing organ
  • Caytonia -- ovule

References[edit]

  1. ^ a b Niklas, Karl J. (1997). The Evolutionary Biology of Plants. University Of Chicago Press. p. 470. ISBN 978-0-226-58083-8. 
  2. ^ National Academy of Sciences (2000). Ayala, Francisco J.; Fitch, Walter M.; Clegg, Michael T., eds. Variation and Evolution in Plants and Microorganisms: Toward a New Synthesis 50 Years after Stebbins. National Academies Press. p. 352. ISBN 978-0-309-07099-7. 
  3. ^ a b c d Arnold, Chester (1947). An Introduction To Paleobotany. Miller Press. p. 428. ISBN 978-1-4067-1861-4. 
  4. ^ Schwendemann, Andrew B.; George Wang; Meredith L. Mertz; Ryan T. McWilliams; Scott L. Thatcher; Jeffrey M. Osborn (2007). "Aerodynamics of saccate pollen and its implications for wind pollination". American Journal of Botany (Botanical Society of America) 94 (8): 1371–1381. doi:10.3732/ajb.94.8.1371. PMID 21636505.