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Showing results for tags 'pteridosperm'.
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Went to a site in central PA today and collected some Llewelyn formation ferns and other Carboniferous plants. Second opinions on the following are appreciated! 1, I thought this is an Alethopteris but the leaves look like they can also be some immature Neuropteris with compound leaves with the leaves pressed together. 2. Is this Sigillaria bark? 3. Wasn’t sure if this is Lepidodendron bark. These crosshatched stem-looking prints are quite common at the site 4. is this a Calamite print? 5. I am fairly certain this is Neuropteris but just would like to be sure. That’s all. All and any help is appreciated! Thanks in advance and let me know if scale is needed.
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Trigonocarpus - Carboniferous Seed from St. Clair (1a)
hitekmastr posted a gallery image in Member Collections
From the album: Carboniferous Plant Fossils in My Collection
This 2 inch Trigonocarpus is a seed of a Medullosa (pteridosperms seed plants) which grew in shallow swamps abour 306-308 million years ago when St. Clair, PA was located near the Equator. Leaves associated with this seed & tree include Alethopteris and Neuropteris. It is thought that these seeds were encased in fleshy "fruit" like an avocado. The seeds were open at the pointed end to allow pollen to enter when the seeds dropped into the water in the shallow swamps where these trees grew. These were the largest Carboniferous seeds, growing up to 4 inches. -
To start I quote some brief information from the Wiki about pteridosperms. The term Pteridospermatophyta (or "seed ferns") refers to several distinct groups of extinct seed-bearing plants. The oldest fossil evidence of plants of this type is of late Devonian age, and they flourished particularly during the Carboniferous and Permian periods. Pteridosperms declined during the Mesozoic Era and had mostly disappeared by the end of the Cretaceous Period. Nowadays, four orders of Palaeozoic seed plants tend to be referred to as pteridosperms: Medullosales, Lyginopteridales, Callistophytales and Peltaspermales. I have the specimens for first two ones only. So, go ahead. First group Medullosales - Neuropteris, Alethopteris, Odontopteris, Reticulopteris, Cyclopteris. Most medullosaleans were small to medium sized trees. The largest were probably the trees with Alethopteris fronds - these fronds could be at least 7 metres long and the trees were perhaps up to 10 metres tall. Especially in Moscovian times, many medullosaleans were rather smaller trees with fronds only about 2 metres long, and apparently growing in dense, mutually supporting stands. During Kasimovian and Gzhelian times there were also non-arboreal forms with smaller fronds (e.g. Odontopteris) that were probably scrambling or possibly climbing plants. Neuropteris and Cyclopteris Alethopteris Odontopteris Reticulopteris Second group Lyginopteridales - includ Lyginopteris, Eusphenopteris, Diplothmema, Palmatopteris, Karinopteris, Mariopteris. In most cases the amount of secondary wood was limited suggesting they were stems of scrambling or climbing plants. The stele is surrounded by a zone of cortex, which in many genera contains bands of fibrous tissue. This fibrous tissue often results in distinctive markings on the surface of the stems even when preserved as adpressions and can help with their generic identification: Lyginopteris for instance shows a mesh-shaped patterning on the surface of the stems. Mariopteris
