Definition - What does Sorus mean?
In botany, the sorus refers to the cluster of spore production that occurs on the underside of fern leaves. In lichens and some types of fungi, the sorus may be surrounded by a secondary external layer. When it grows on ferns, the sori is normally distinguishable by its yellow to brownish color.
MaximumYield explains Sorus
Depending on the plant, the sorus may be covered by indusium, a thin tissue that either covers or scales the surface during the developmental stage. Some botanists use the sorus location, arrangement, and shape to identify different types of ferns.
For example, certain sori may be linear or circular, while others are mainly arranged in oblique rows. In some cases, it is also possible to recognize fern taxa either by the absence or presence of indusium.
The sorus is primarily composed of small, circular bodies known as the sporangia.