Australian Plants Society Tasmania Inc.

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The Story of Gondwana. Ancient Flora.

Ancient Flora

Quoting from Mary White’s The Greening of Gondwana1, ‘The Age of Conifers and Cycads’

“The Jurassic Period was uniformly warm to hot and wet worldwide, and there was a luxuriant cosmopolitan flora of Conifers, Cycads, Ferns, Seed-ferns, Ginkgos, and herbaceous Lycopods and Horsetails. The flora, which continues into the Early Cretaceous, is the last to be composed of plants from ancient groups only. After the Jurassic, the changeover to modern-aspect flora commenced.”

Athrotaxis cupressoides and A. selaginoides of the Cupressaceae or Cypress family, are endemic to Tasmania, and belong to the readily identifiable group of plants known as the conifers,2 and are related to the ancient Jurassic Period conifers. Fossils of these ancient conifers have identical leaf structures and very similar fruit forms.

Fern fossils are very common for the Jurassic Period, Cyathea australis and C. cunninghamii are Tasmanian species of this very ancient fern family.

Fern fossils similar to the Dicksonia antarctica fiddlehead have been found, similarly fern fossil cross sections like the Dicksonia antarctica trunk cross section have been also found.

The Cycad fossil image has leaf form similar to the leaf forms of the Zamia palm photo. Cycad fruit fossils have also been found, similar in form to that of the Zamia palm.

The term Seed-ferns (Pteridospermatophyta) refers to several distinct groups of extinct seed plants, the Spermatophytes. Pteridosperms declined during the Mesozoic Era and mostly disappeared by the end of the Cretaceous, though some pteridosperm-like plants seem to have survived into Eocene times in Tasmania.3 Rhacopteris were a genus of Seed-fern fossils, from the Late Carboniferous period, which have been found in New South Wales.

Ginkgo biloba, according to Wikipedia, the free encyclopaedia, is the only living species in the division Ginkgophyta, family Ginkgoaceae, the few others that may have existed, now being extinct. It is found in fossils dating back 270million years and is native to China. It has been widely cultivated since early in human history, especially in Japan and Korea, and has various uses in traditional medicine and as a food source.  Reference can be found to Ginkgo fossils in the northern supercontinent, Laurasia, which had been joined to Gondwana in the larger supercontinent of Pangaea. Cycads are said to be the closest living relatives to Ginkgos.

Club moss fossils specimens similar in foliage to that shown in the Lycopodium fastigiatum picture have been found and dated to the Jurassic Period.

Horsetails are rushlike plants with only one surviving genus, Equisetum, and are not found in Australia, so are not covered in this page. They are a class in the plant division, Pteridophyta which includes the ferns.4

  1. The Greening of Gondwana, 3rd edition, 1998, Mary E. White, Kangaroo Press and imprint of Simon and Schuster, p157.
  2. Tasmania’s Natural Flora, 2nd edition 2012, Christine Howells, Editor, Australian Plants Society Tasmania Inc., Hobart Group, p6.
  3. Quoted from the Wikipedia internet page on Seed fern, https://simple.wikipedia.org/wiki/Seed_fern
  4. Information from the Wikipedia internet page on Equisetum, https://en.wikipedia.org/wiki/Equisetum.