Translations:Adventist Youth Honors Answer Book/Nature/Ferns/14/en

4. How do spores travel from the parent plant to a new location? How long does it take a spore to develop into a mature plant? Observe from live ferns or pictures how a young fern is different from an adult fern.

Spores are stored by the fern in tiny cases called sporangia. These spore cases are massed together into a sorus (plural sori) which is visible to the naked eye on the underside of a fertile frond (not all fronds are fertile). The spore case is encircled by a ring consisting of a single layer of cells called an annulus. This ring goes almost all the way around the spore case. As the spore case dries out, it becomes brittle until it finally splits open. Since the ring is stronger than the rest of the spore case, it slowly pulls the case open. When water tension is released, the ring suddenly snaps, throwing spores out away from the fern at great speed. Because spores are so tiny (invisible to the naked eye), even the slightest breeze will carry them great distances.