Leptosporangiate fern

Many ferns belong to this big group.

They live all over the world. Some grow on trees. There are many kinds of these ferns.

These ferns have tiny parts. These parts make seeds for new plants. A thin ring helps push them out.

Some of these ferns are very old. We can find their remains in rocks. These are called fossils.

It is fun to look for ferns!

Most ferns belong to a big group. We call them leptosporangiate ferns. There are about 8,465 kinds of these ferns living today.

These ferns get their name from tiny parts. These parts are called sporangia. They make spores to grow new plants. In these ferns, each part starts from just one cell. This is different from other ferns. The walls of these parts are very thin. They are only one cell thick. Many ferns have a special ring called an annulus. This ring helps to shoot the spores out. Some ferns also have a scale called an indusium. This scale can cover the spores like a cup or a ring.

Some of these ferns are epiphytes. This means they grow on other plants. Almost one third of these ferns do this. We can also find very old ferns in rocks. These are called fossils. Some fossils come from the Lower Jurassic time. These fossils help us learn about the past.

Leptosporangiate ferns are a huge group of living plants. They are the largest group of all ferns on Earth. Scientists believe there are about 8,465 different species in this group. This is much more than all other ferns combined. Other ferns only have about 2,070 species. This means most ferns you see are likely in this group.

These ferns have a special way of making spores. They use tiny parts called sporangia to do this. In these ferns, each sporangium starts from just one single cell. Other ferns use a whole group of cells instead. The walls of these sporangia are very thin. They are only one cell thick. Many of these ferns have a ring called an annulus. This ring works like a tool to eject the spores. Some ferns also have a scale called an indusium. This scale can look like a cup or a ring around the spores.

People have studied these ferns for a long time. A scientist named Karl Ritter von Goebel first named them in 1881. Later, Christian Luerssen helped group them in 1884. In 1966, researchers like Cronquist, Takhtajan, and Zimmermann used the name Polypodiidae. This name comes from a type of fern called Polypodium. Scientists still change how they group them today. They use new tools to see how plants are related.

There are many facts to know about these plants. About one third of these species are epiphytes. Epiphytes are plants that grow on other plants. Scientists use molecular studies to learn about their history. These studies look at the tiny parts inside cells. The group is now divided into seven orders. There are 44 families and 300 genera in this group. Some experts estimate there are 10,323 species in total.

We can even find these ferns in the history of the Earth. They have a very large fossil record. Some fossils come from the Lower Jurassic period. One example is a family called Dicksoniaceae. These old fossils help us understand how plants changed. Even though some families are extinct, they tell a story. They show us how life has lived for a very long time.

Leptosporangiate ferns are a massive group of living plants. They belong to the subclass Polypodiidae. This group is the largest of all living ferns. Scientists estimate there are about 8,465 species in this group. This number is much larger than all other ferns combined. Other fern groups only have about 2,070 species. Together, all ferns total approximately 10,535 species. These plants are important for understanding plant diversity.

The name leptosporangiate describes how these plants reproduce. They produce spores in tiny structures called sporangia. In this group, each sporangium grows from a single epidermal cell. This is different from eusporangiate ferns. Eusporangiate ferns develop sporangia from a large group of cells. The walls of a leptosporangiate sporangium are very thin. They are only one cell thick. Many of these ferns also have a structure called an annulus. The annulus is a ring around the sporangium. It works to eject the spores into the air. Some ferns also have a scale called an indusium. This scale can cover the whole sorus. It might look like a ring or a cup. In some species, the indusium is very small or absent.

Scientists organize these ferns into many different levels. Current classifications divide the Polypodiidae into seven orders. These plants also include 44 families and 300 genera. Some estimates suggest there are as many as 10,323 species. About one third of these species are epiphytes. An epiphyte is a plant that grows on another plant. This allows them to live in different parts of a forest. The group is distinct from the three other major fern subclasses. Those other groups are often called eusporangiate ferns. They include the Marattiidae, the horsetails, and the whisk ferns.

Our understanding of these ferns has changed over time. Karl Ritter von Goebel first recognized them as a group in 1881. He called them the "Leptosporangiateen." Later, Christian Luerssen helped refine this in 1884. He divided homosporous ferns into two specific groups. In 1966, researchers Cronquist, Takhtajan, and Zimmermann used the name Polypodiidae. This name comes from the fern genus Polypodium. Modern scientists now use molecular phylogenetics to study them. This means they look at DNA and molecules to find relationships. This helps clarify how different plant families are actually related.

Molecular studies have changed how we view fern history. In 2006, Smith and other researchers used molecular data for classification. They included the water ferns, known as Salviniales, in this group. Some older systems placed water ferns in a separate subclass. This is because water ferns have a very modified morphology, or shape. Recent studies show that the common ancestor of certain groups went through a whole genome duplication. This is a major event where the entire set of genetic instructions is doubled. This process helps explain how new plant groups might develop over time.

Leptosporangiate ferns have a very long history on Earth. They have a substantial fossil record that scientists study. For example, fossils of the Dicksoniaceae family exist from the Lower Jurassic period. This family belongs to the order Cyatheales. There are many other extinct families known from fossils. Some of these include Anachoropteridaceae and Botryopteridaceae. Other extinct groups include Kaplanopteridaceae and Psalixochlaenaceae. Because these plants are extinct, they are not in modern classification systems. They provide a window into how plants looked millions of years ago.

Classification systems for these ferns are still evolving. In 2014, Christenhusz and Chase grouped all fern subclasses into Polypodiophyta. In 2016, the Pteridophyte Phylogeny Group adopted the name Polypodiopsida. These modern names help scientists communicate clearly about plant evolution. Some experts argue that molecular studies might be skewed. They say these studies sometimes ignore fossil evidence. However, molecular information has helped fix old mistakes. It has clarified relationships between families that seemed unrelated. This helps us build a more accurate tree of life for all plants.