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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?
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Trigonocarpus - Carboniferous Seed from St. Clair (1a)
hitekmastr posted a gallery image in Members Gallery
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 Pe
