Ferns : The oldest inhabitants of our planet
The Earth's environment is strikingly varied, showcasing a wide range of plant species that include herbaceous, tree-like, and shrubby forms. Many recognize from their basic biology lessons that long ago, our planet was home to enormous tree-like ferns.
The earliest of these giant plants made their appearance over 400 million years ago during the Paleozoic era, specifically in the Devonian period. However, after thriving for approximately 100 million years, these magnificent ferns began to decline, and this trend of extinction is still ongoing in today's world.
Throughout history, some plant species have vanished completely from the Earth's surface, while others have managed to endure the catastrophic events that impacted the planet. These resilient species adapted to the new environmental conditions and evolved into different forms, including herbaceous and liana-like varieties.
Despite many changes in the Earth's ecosystems, some ferns continue to astound us with their impressive sizes. Most ferns thrive in damp environments and prefer shady conditions, and notably, these ancient plants played a crucial role in forming coal deposits over millions of years.
Tree ferns are a specific group within the fern family. Almost all of the tree fern species from ancient periods have become extinct, unable to cope with significant climate shifts. However, a few varieties still exist in swampy areas found within tropical and subtropical forests. Currently, there are more than 10,000 species of ferns, but only around 700 of them are tree-like.
Many of these tree ferns are now endangered, prompting botanists to cultivate them in controlled environments like greenhouses and botanical gardens to ensure their survival.
In ancient eras, tree ferns towered at heights of up to 25 meters, with trunk diameters reaching as wide as 0.5 meters. In contrast, modern tree ferns are much smaller, seldom reaching heights above 15 meters.
However, their trunk diameters can be quite large, exceeding 0.8 meters in some cases, and their leaves can measure between 6 to 10 meters in length. Due to their size and characteristics, these ferns can often be mistaken for their herbaceous relatives.
The fern family is the most diverse group of these ancient plants, thriving in nearly every environment. They can be found in mountains, forests, deserts, and tropical regions.
The polyhorned fern subclass is particularly common and can survive in the shady forests of Russia, although some species thrive in bright and sunny locations as well. This subclass includes both toxic and medicinal plant species.
For instance, the low-growing brittle bladderwort, found on rocky surfaces, possesses extremely toxic leaves. Despite their poisonous nature, some ferns can provide medicinal benefits. The male shield fern, which is toxic and grows in moist deciduous and coniferous forests, produces extracts with healing properties from its rhizome.