Question

characteristics of fern

Answer 1

Spore-producing ferns (the one we usually see) are asexual and consist of basic roots, stems and fronds (leaves). The fronds often consist of leaflets referred to as pinnae. On some or all of the leaves, or sometimes on just one specialized portion of a special leaf, are the structures called sporangia. These are usually clustered into groups called sori, which are the visible dark round things on the bottom of the fronds. Sometimes the sori are protected by flaps or disk structures called indusia, or covered by the rolled over edge of the pinnae.

The sporangia produce microscopic spores, which are released at the appropriate season and scattered by the wind. Those that find the right conditions develop into a small sexual generation plant called a prothallia. Each of these short-lived intermediate plants produce a few eggs and/or many sperm cells. The sperm require a film of water on the plants to swim over to the flask-like structures that hold the eggs. This is one reason why ferns live in damp, shaded areas where condensation from fog and dew is common.

The fertilized egg develops into a new spore-producing fern, living off the prothallia until it develops enough roots and fronds to survive on its own, at which time the prothallia dies off.