Flora
And now, let's move on to living things, such as plants. There's a lot of ground to cover, so to speak, so let's get to it. There is no evidence of a mass extinction of plants at the Triassic/Jurassic boundary, although some species did decline or even die out in some areas.
Conifers form a dominant component of Jurassic floras, when they underwent a major time of diversification. Most modern conifer groups appeared by the end of the Jurassic.
The oldest definitive record of the cypress family is from the Early Jurassic and were found in Patagonia (the southern area of South America). By the middle of the Jurassic, the cypress were abundant in warm temperate-tropical regions of the Northern Hemisphere.
Ancestors of the current pine family were widely distributed across Eurasia during the Jurassic.
The flora of the mid-latitudes of Eastern Asia were dominated during the Early Jurassic by a broad leafed conifer which shed its leaves seasonally, and which is not closely related to any living family of conifer. It extended northwards into polar latitudes of Siberia, and then contracted northward because of increasing aridity of the region.
Evidence of the yew family have been found in Sweden, England and China dating from the Middle Jurassic. They appear to be closely related to modern yew specimens.
Ginkgoales—which today has only one living specie, the Ginkgo biloba—were more diverse during the Jurassic, and were among the most important components of Eurasian Jurassic flora, adapted to a wide variety of climatic conditions.
Bennettitales are a group of seed plants that reached a peak diversity during the Triassic and Jurassic periods. Although they bear some resemblance to cycads, they are not believed to be closely related to them. All Jurassic Bennettitales grew as shrubs and small trees, and were adapted to grow in open habitat with poor soil. They also had flower-like reproductive structures that are thought to have been pollinated by insects.
Cycads reached their apex of diversity during the Jurassic and Cretaceous (which comes next) periods. Although this era is sometimes called the 'Age of Cycads', cycads are thought to have been a relatively minor component of Jurassic flora. Their foliage is often confused with that of Bennettitales and other plants. Cycads are thought to have been mostly confined to tropical and subtropical latitudes.
There are no widely accepted Jurassic records of true flowering plants, and fossil evidence suggests that the group diversified during the period following the Jurassic.
'Seed ferns' is a collective term to refer to fern-like plants that produce seeds but have uncertain affinities to living seed plant groups. One prominent group of seed ferns reached their zenith during the Jurassic and was widespread in the Northern Hemisphere, although records in the Southern Hemisphere are rare.
Another group of seed plants are known from the Late Triassic through the Jurassic to the Cretaceous. They are thought to have been tree- or shrub-like, and formed a conspicuous component of Northern Hemisphere Mesozoic temperate and warm-temperate floras. Another group of seed plants called the Pentoxylales, first appeared during the Jurassic, but appear to have been confined to Gondwana.
Many living families of fern were widespread during the Jurassic period. The Polypodiales ferns, which make up 80% of living fern diversity, have no record from the Jurassic and are thought to have diversified later, during the Cretaceous.
The oldest remains of modern horsetails first appear in the Early Jurassic. I could have sworn I heard mention of horsetails in earlier periods, but those must not have made it to modern times.
The Cyatheales, the group containing most modern tree ferns, appeared during the late Jurassic.
Quillworts that are virtually identical to modern species are known from the Jurassic onwards.
Various mosses have left fossil records from the Jurassic and are believed to be related to modern mosses. Several records of liverwort have also been found from the Middle Jurassic.
https://en.wikipedia.org/wiki/Jurassic
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