**Ferns reproduce through spore formation.**

Ferns are a type of vascular plant that reproduce through spores. Spore formation is a method of asexual reproduction where the parent plant produces spores that can develop into new individuals without the need for fertilization or the production of seeds.

Here is a detailed explanation of how ferns reproduce through spore formation:

**1. Life Cycle of Ferns:**
The life cycle of ferns alternates between two distinct generations - the gametophyte and the sporophyte. The gametophyte is a small, independent plant that produces eggs and sperm, while the sporophyte is the main fern plant we commonly see.

**2. Sporangia:**
On the undersides of fern leaves, there are small structures called sporangia. These sporangia are responsible for producing and releasing spores. Each sporangium contains numerous spores.

**3. Spore Production:**
Within the sporangium, specialized cells called sporocytes undergo meiosis to produce haploid spores. Meiosis is a type of cell division that halves the number of chromosomes, resulting in haploid cells with only one set of chromosomes.

**4. Spore Release:**
When the spores are mature, the sporangium dries out and eventually bursts open, releasing the spores into the environment. The spores are lightweight and have a protective outer layer, enabling them to be carried by wind or water to new locations.

**5. Germination and Growth:**
If the spore lands in a suitable environment with sufficient moisture, it can germinate and develop into a gametophyte. The gametophyte is a small, heart-shaped plant called a prothallus. It grows from the spore and produces both male and female reproductive structures.

**6. Fertilization:**
In the gametophyte, specialized structures called antheridia produce sperm, and archegonia produce eggs. The sperm swim through a film of water to reach the eggs, and fertilization occurs, resulting in the formation of a zygote.

**7. Sporophyte Development:**
The zygote develops into a new sporophyte, which is the familiar fern plant. The sporophyte grows from the gametophyte and eventually becomes independent.

**8. Spore Production (Repeat):**
Once the sporophyte is mature, it develops sporangia on the undersides of its leaves. The sporangia produce and release spores, continuing the cycle of spore formation and reproduction in ferns.

In conclusion, ferns reproduce through spore formation, which involves the production and release of spores from sporangia. The spores develop into gametophytes, which produce eggs and sperm. Fertilization occurs, leading to the development of a new sporophyte fern plant that produces spores. This life cycle alternates between the gametophyte and sporophyte generations.