9.10: Life Cycle of Seedless Vascular Plants

What's a fiddlehead?

This fern leaf structure is known as a fiddlehead. Can you understand why? Does it look tasty? Nearly all ferns have fiddleheads, and many recipes exist on how to prepare fiddleheads. But this part of the plant, the leaf or the frond, also plays a very important role in the fern's life cycle.

Life Cycle of Seedless Vascular Plants

Unlike nonvascular plants, all vascular plants—including seedless vascular plants—have a dominant sporophyte generation. Seedless vascular plants include clubmosses and ferns. Figure below shows a typical fern life cycle.

In the life cycle of a fern, the sporophyte generation is dominant.

A mature sporophyte fern has the familiar leafy fronds. The undersides of the leaves are dotted with clusters of sporangia. Sporangia produce spores that develop into tiny, heart-shaped gametophytes. Gametophytes have antheridia and archegonia. Antheridia produce sperm with many cilia; archegonia produce eggs. Fertilization occurs when sperm swim to an egg inside an archegonium. The resulting zygote develops into an embryo that becomes a new sporophyte plant. Then the cycle repeats.

Summary

• In vascular plants, the sporophyte generation is dominant.
• In seedless vascular plants such as ferns, the sporophyte releases spores from the undersides of leaves.
• The spores develop into tiny, separate gametophytes, from which the next generation of sporophyte plants grows.

Review

1. What role do leaves play in the reproduction of ferns?
2. Describe antheridia and archegonia and their functions.
3. Create your own cycle diagram to represent the life cycle of a fern.

Image	Reference	Attributions
	[Figure 1]	Credit: Mariana Ruiz Villarreal (LadyofHats) for CK-12 Foundation License: CC BY-NC
	[Figure 2]	Credit: Mariana Ruiz Villarreal (LadyofHats) for CK-12 Foundation Source: CK-12 Foundation License: CC BY-NC 3.0