The Jurassic period, stretching from roughly 201 to 145 million years ago, was dominated by plant groups that look unfamiliar to most people today. Conifers, cycads, ginkgos, ferns, and horsetails formed the backbone of nearly every terrestrial ecosystem, while flowering plants were either absent or vanishingly rare. The world was warmer, wetter, and greener than our own, with forests pushing into polar latitudes and no grasslands anywhere on Earth.
A Warmer World With Forests at the Poles
To understand Jurassic vegetation, you need to picture a planet with a radically different climate. Global temperatures ran roughly 5 to 10°C warmer than today, atmospheric carbon dioxide levels were at least four times higher than modern concentrations, and the oceans were warmer from surface to seabed. That extra warmth drove a much more vigorous water cycle, with higher humidity and more rainfall overall, though large continental interiors still hosted vast deserts.1Proceedings of the Geologists’ Association. Jurassic climates There were no permanent polar ice caps. Dense forests grew within a few degrees of both poles, enduring months of continuous summer daylight followed by months of winter darkness. This warm, ice-free world gave plants access to land area that is frozen tundra or ice sheet today.
The distribution of plant types tracked climate zones across these ancient continents. Cooler, wetter high latitudes favored deciduous ginkgo relatives that could shed their leaves during the long polar winter. Warmer subtropical zones were ruled by cycads and their look-alikes. Conifers occupied a huge range of habitats, from tropical lowlands to upland forests near the poles.2The Paleontological Society Special Publications. Global Jurassic floras and climate The absence of grasses and flowering shrubs meant the ground-level vegetation looked nothing like a modern landscape. Where you might expect a meadow or a thicket of bushes today, Jurassic ecosystems had carpets of ferns, thickets of cycad-like plants, and mats of mosses and liverworts.
Conifers Ruled the Canopy
Conifers were the tall trees of the Jurassic, forming the forest canopy across most of the globe. But these were not the pines, spruces, and firs you see today. The most important Jurassic conifer families have either gone extinct or shrunk to small remnant populations. The Cheirolepidiaceae, for example, were one of the most widespread and abundant conifer families during the Jurassic and much of the Mesozoic. They produced small, scale-like leaves and were adapted to a wide range of environments, from arid lowlands to coastal habitats. Fossils of their distinctive pollen, called Classopollis, turn up on every continent. The family eventually went extinct alongside the dinosaurs at the end of the Cretaceous.
Another major group was the Araucariaceae, which survives today as the monkey puzzle tree and the Norfolk Island pine but was far more diverse and widespread in the Jurassic. Fossil seed cones from the two families can actually be difficult to tell apart, which has complicated efforts to map their ancient ranges and diversity.3PubMed. A new Cheirolepidiaceae (Coniferales) from the Early Jurassic of Patagonia (Argentina): Reconciling the records of impression and permineralized fossils Other conifer families present during the Jurassic included the Podocarpaceae (now mostly confined to the Southern Hemisphere) and early members of the Cupressaceae, the family that today includes cypresses, junipers, and redwoods. Together, these conifers would have given Jurassic forests a broadly recognizable silhouette from a distance, with tall evergreen crowns overhead, but the species filling those crowns were entirely different from anything in a modern temperate or boreal forest.
Cycads, Bennettitales, and the “Age of Cycads” Misnomer
The Jurassic is sometimes called the “Age of Cycads,” which is both partly true and somewhat misleading. Cycads were genuinely abundant, with palm-like trunks and stiff, compound leaves forming a conspicuous part of the understory and mid-canopy in warm regions. Genera like Nilssonia, Ctenis, and Otozamites are common in Jurassic fossil beds from subtropical and tropical latitudes.2The Paleontological Society Special Publications. Global Jurassic floras and climate But much of what was historically lumped together as “cycads” in older paleobotany was actually Bennettitales, a completely separate order of seed plants that happened to look strikingly similar on the outside.
Bennettitales had trunks and leaves that could pass for cycads at a glance, but their reproductive structures were fundamentally different. Some bore flower-like reproductive organs with both pollen-producing and seed-bearing parts grouped together in a single structure, something true cycads never do. Bennettitales were enormously successful during the Jurassic and Early Cretaceous before going completely extinct. Their superficial resemblance to cycads fooled early fossil collectors and inflated estimates of cycad diversity. Modern work has disentangled the two groups, but the “Age of Cycads” label persists even though it would be more accurate to call it the age of cycads and bennettitaleans together.
Ginkgos and Their Vanished Relatives
Today, the maidenhair tree, Ginkgo biloba, is the sole surviving species of an ancient lineage. In the Jurassic, ginkgo relatives were diverse and geographically widespread, forming a major component of temperate and high-latitude forests. The group included not just Ginkgo itself but also genera like Czekanowskia, Phoenicopsis, and Baiera, which bore narrow, strap-shaped leaves quite unlike the distinctive fan-shaped leaf of the modern maidenhair tree.2The Paleontological Society Special Publications. Global Jurassic floras and climate
These ginkgo relatives were deciduous, meaning they dropped their leaves seasonally. That trait made them well suited to the high-latitude forests near the poles, where months of winter darkness meant photosynthesis was impossible for part of the year. Fossil leaf mats from these polar forests show thick accumulations of shed ginkgophyte leaves, much like the leaf litter you would find on a forest floor in autumn today, but composed entirely of non-flowering plants. The dominance of ginkgo relatives in cool-wet climates and cycads in warm-dry climates gave paleobotanists one of their most reliable tools for reconstructing Jurassic climate zones from the plant fossil record.
Ferns, Horsetails, and the Forest Floor
Beneath the conifer canopy and around the cycad thickets, ferns formed the primary ground cover across much of the Jurassic world. Several fern families that are still around today were already well established, including the Osmundaceae, the royal fern family. Exceptionally preserved fossils of osmundaceous ferns from the Early Jurassic of Sweden show rhizomes cloaked in thick mantles of old leaf bases and roots, looking almost identical to their modern descendants. Those fossils have even preserved epiphytes and microorganisms living on the fern, offering a snapshot of an entire forest-floor micro-ecosystem.4ScienceDirect. Biotic interactions in an exceptionally well preserved osmundaceous fern rhizome from the Early Jurassic of Sweden
Horsetails, the genus Equisetum and its relatives, occupied the wetland margins of rivers, lakes, and swamps. Modern horsetails are small, rarely more than a meter tall in most species, but their Jurassic ancestors could grow considerably larger. The lineage is astonishingly ancient. Fossil evidence suggests horsetails have retained their basic body plan since at least the Jurassic and possibly back to the Triassic, making Equisetum a contender for the oldest surviving genus of vascular plants on Earth.5PubMed Central. Horsetails Are Ancient Polyploids: Evidence from Equisetum giganteum Mosses, liverworts, and other bryophytes rounded out the ground-level flora, especially in moist habitats near streams and in shaded forest interiors.
How Jurassic Plants Reproduced Without Flowers
Without flowering plants dominating the landscape, pollination in the Jurassic worked differently than it does today, but not as differently as you might assume. Wind pollination was widespread among conifers, ginkgos, and some other groups, just as it is in their living relatives. But insect pollination was already well established too. Fossil evidence shows that insects were visiting and pollinating gymnosperms and Bennettitales long before flowering plants evolved, with relationships that were just as complex and specialized as those between modern bees and flowers.6PubMed Central. Evolution of Insect Pollination Before Angiosperms and Lessons for Modern Ecosystems
The evidence for these ancient partnerships comes from multiple lines. Certain Mesozoic insects had elongated mouthparts built for reaching into seed cones to drink pollination drops, the sticky fluid many gymnosperms produce to capture pollen. Pollen types consistent with insect transport, rather than wind dispersal, show up across conifers, cycads, bennettitaleans, and seed ferns.7TAXON. Pollination drops, pollen, and insect pollination of Mesozoic gymnosperms So the popular image of a Jurassic world with only crude, wind-blown reproduction is wrong. Insects and plants had already been co-evolving for tens of millions of years by the time the Jurassic began.
Seed dispersal strategies were varied as well. Studies of Middle Jurassic to Early Cretaceous plant assemblages show that wind dispersal, using winged seeds or feathery attachments, was a key strategy throughout the period. Some seeds were likely carried by water, particularly those of aquatic plants that produced small, smooth seeds aggregated into detachable pods. Evidence for animal dispersal via ingestion also exists: smooth, unadorned seeds have turned up inside fossilized gut contents and coprolites. Interestingly, despite the rise of feathered dinosaurs and early fur-bearing mammals during this interval, there is very little evidence that seeds hitchhiked on the outside of animals the way modern burrs and hooks do.8Palaeogeography, Palaeoclimatology, Palaeoecology. Plant mobility in the Mesozoic: Disseminule dispersal strategies of Chinese and Australian Middle Jurassic to Early Cretaceous plants
Feeding the Dinosaurs
A longstanding assumption held that Jurassic plants, especially gymnosperms and ferns, were nutritionally poor compared to modern grasses and flowering plants. That assumption has been overturned. Laboratory fermentation experiments, using modern relatives of Jurassic plant families as stand-ins, have shown that conifers, ferns, and horsetails can be just as digestible as angiosperm grasses and broadleaf plants. Araucariaceae foliage and horsetails are consistently high in digestible energy across different species and growing conditions, while fern digestibility varies more from family to family.9PubMed Central. Digestibility of dinosaur food plants revisited and expanded: Previous data, new taxa, microbe donors, foliage maturity, and seasonality
This matters because it changes how we think about the ecology of giant herbivorous dinosaurs like sauropods and stegosaurs. If the vegetation available to them had been as low in energy as earlier researchers assumed, it would have been hard to explain how animals weighing tens of tonnes sustained themselves. The revised picture, where Jurassic-age plant families offered plenty of calories, fits much better with the existence of enormous herbivores. It also suggests that the rise of flowering plants in the Cretaceous was not driven by a nutritional advantage over the plants they replaced. Angiosperms won out for other reasons.
Not All Green and Lush
It is tempting to picture the entire Jurassic as a wall-to-wall tropical forest, but the reality was more varied. The Morrison Formation of the western United States, one of the richest dinosaur-bearing rock units in the world, preserves a Late Jurassic landscape that was surprisingly open. The plant fossils found there suggest a predominantly herbaceous vegetation rather than dense forest. Wood fossils are uncommon even in sediments where preservation conditions should have favored them, implying that large trees were genuinely scarce in parts of this landscape.10Sedimentary Geology. Jurassic “savannah” – Plant taphonomy and climate of the Morrison Formation (Upper Jurassic, Western USA) Researchers have compared the Morrison environment to a kind of Jurassic savannah, dominated by low-growing ferns, ground-hugging plants, and scattered trees rather than closed-canopy woodland.
Meanwhile, other regions tell a very different story. The Yorkshire coast of England has yielded hundreds of plant-fossil localities from Jurassic-aged rocks, showing a flora that persisted through multiple geological stages but shifted in composition over time.11Proceedings of the Yorkshire Geological Society. The Geology of the Yorkshire Jurassic Flora And in the Southern Hemisphere, some of the plant lineages present in Jurassic Patagonia can be traced forward to components of today’s South American flora, forming a botanical thread spanning over 150 million years. Fire also played a role in shaping these landscapes. Charcoal deposits and chemical markers of combustion found across Central Europe indicate that wildfires were widespread during the Late Triassic and Early Jurassic, with the most intense fire activity in the earliest Jurassic. Calculated burn temperatures are consistent with ground-level or near-surface fires, the kind that clears understory vegetation rather than incinerating entire forests.12PALAIOS. Widespread Upper Triassic to Lower Jurassic Wildfire Records from Poland: Evidence from Charcoal and Pyrolytic Polycyclic Aromatic Hydrocarbons These fires would have shaped plant community structure, favoring species that could resprout from roots or quickly recolonize burned ground.
Were There Any Flowering Plants in the Jurassic?
This is one of the most contested questions in paleobotany. The traditional view places the origin and diversification of flowering plants (angiosperms) firmly in the Cretaceous period, after the Jurassic had ended. Charles Darwin famously called the apparently sudden appearance of flowers in the fossil record an “abominable mystery.” But several claimed Jurassic angiosperm fossils have emerged in recent decades, mostly from northeastern China. These include genera like Schmeissneria, Xingxueanthus, Juraherba, and Nanjinganthus, the last of which has features like a cup-shaped receptacle and an inferior ovary that are found in flowering plants but not in known gymnosperms.13eLife. An unexpected noncarpellate epigynous flower from the Jurassic of China
Not everyone is convinced these are true angiosperms. Critics have argued that some features could belong to unusual gymnosperms or seed ferns, and the fossils remain debated. Molecular clock studies, which use DNA mutation rates in living species to estimate when lineages diverged, have offered some support for a pre-Cretaceous origin. Recent analyses place the crown age of angiosperms somewhere in the Triassic period, roughly 255 to 202 million years ago, which would mean the lineage existed well before the Jurassic even began, though it may have remained inconspicuous for a very long time.14PubMed Central. New insights on angiosperm crown age based on Bayesian node dating and skyline fossilized birth-death approaches
If these molecular estimates are right, flowering plants may have been present during the Jurassic as rare, ecologically marginal members of the flora, perhaps small herbs tucked into disturbed habitats or wet margins. They would not have been a significant part of any Jurassic landscape. The explosive diversification that turned angiosperms into the dominant plant group on Earth did not happen until the mid-Cretaceous, tens of millions of years later.
What Happened to All These Plants?
The transition from a gymnosperm-dominated world to a flowering-plant-dominated world is one of the great ecological transformations in Earth’s history, but it was not a sudden catastrophe. It played out over tens of millions of years during the Cretaceous. Gymnosperms did not vanish overnight; instead, angiosperms appear to have gradually outcompeted them, particularly in disturbed and early-successional environments where fast growth and rapid reproduction gave flowering plants an edge. Gymnosperms held on longer in mature, stable forest habitats where their slower life history was less of a disadvantage.15Biological Journal of the Linnean Society. The tortoise and the hare: ecology of angiosperm dominance and gymnosperm persistence
Several major Jurassic plant groups survive today in diminished form. Cycads still exist but are limited to about 350 species in tropical and subtropical regions, a shadow of their former diversity. Ginkgo biloba is a single species, often described as a living fossil, kept alive partly by human cultivation. Araucarian conifers persist in scattered Southern Hemisphere populations. Ferns and horsetails remain widespread but occupy smaller ecological niches than they did when there were no grasses or flowering ground cover to compete with. Bennettitales and Cheirolepidiaceae are entirely gone, with no living descendants. The Jurassic flora was not a primitive version of what we have now. It was a fundamentally different plant world, one that functioned perfectly well for over a hundred million years before the flowering plants rewrote the rules.