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For many millions of years, cone-bearing plants and their relatives were among the most successful and important plants on Earth. In some places, they still are, such as the coniferous forests of the Northern Hemisphere. This episode, Aly joins us again to discuss the diversity and history of Gymnosperms.
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“Naked Seeds”
Gymnosperms are vascular, seed-bearing plants which – unlike their cousins, the angiosperms – lack fruit, which is to say their seeds are uncovered (hence, gymnosperm means “naked seeds”).
Modern gymnosperms do not show the same incredible diversity as angiosperms; gymnosperms are essentially all woody plants, all perennial, and are found in a smaller range of habitats. That said, gymnosperms are still found all over the world in a variety of forms both recognizable and bizarre, and some gymnosperms (such as coniferous trees) are often key components of certain biomes.
Gymnosperms include conifers (such as pine, cedar, yew, and more), cycads, the one-of-a-kind Ginkgo biloba, and the rare and unusual gnetophytes.
Top left: A forest of Douglas fir (Pseudotsuga menziesii). Image by Dave Powell, CC BY 3.0
Top right: The cycad called Sago Palm (Cycas revoluta). Image by Dinesh Valke, CC BY-SA 2.0
Bottom left: Ginkgo biloba. Image by Magnus Manske, CC BY-SA 3.0
Bottom right: Welwitschia mirabilis, a gnetophyte. Image by Sara&Joachim, CC BY-SA 2.0
Gymnosperms Through Time
Before the gymnosperms were the aptly-named Progymnosperms, a group that survived from the Devonian to the Permian. True gymnosperms appear in the fossil record during the Carboniferous, and by the late Carboniferous they had developed into a diverse, widespread, and familiar array of trees and other plants.
Top left: Petrified cones of Araucaria from Jurassic Argentina. Image by Brocken Inaglory, CC BY-SA 3.0
Top right: Fossil Ginkgo leaf from Eocene Washington, USA. Image by Kevmin, CC BY-SA 4.0
Bottom: Fossil conifer (Elatides) from Cretaceous North America. Image by James St. John, CC BY 2.0
From roughly 350-100 million years ago, gymnosperms were some of the most important and successful plants in the world, defining habitats worldwide. These included ancient members of familiar groups like conifers and cycads as well as prominent extinct groups such as the cycad-like Bennettitales. Things changed during the Cretaceous with the rise of angiosperms, which would go on to become extraordinarily diverse, out-competing gymnosperms in many environments. Today, angiosperms are more common, but gymnosperms continue to be the major group plants in many cold and arid habitats.
Photo provided by Dr. Aly Baumgartner (thanks, Aly!)
Learn More
Beyond Pine Cones: An Introduction to Gymnosperms
The timescale of early land plant evolution (technical)
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If you enjoyed this topic and want more like it, check out these related episodes:
- Episode 57 – Evolution of Flowering Plants (Angiosperms)
- Episode 73 – Trees
- Episode 115 – Biomes
- Episode 135 – Seeds
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COMMON DESCENT 
As always, Dr Baumgartner is very informative. She’s also very enthusiastic and entertaining.
Your listeners — or at least this listener — hopes she’ll start visiting more often.
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