AP BIOLOGY

Detailed explanation-1: -Sori (singular: sorus) are groups of sporangia (singular: sporangium), which contain spores. Sori are usually found on the underside of the blade. Young sori are commonly covered by flaps of protective tissue called indusia (singular: indusium).

Detailed explanation-2: -Sporangia are produced on the underside of leaves in clusters called ‘fruit dots’. There is a flap of tissue called an indusium that covers the cluster of sporangia. Fronds and stipe of a Dryopteris fern, showing ‘fruit dots’ (clusters of sporangia) on the undersides of leaves.

Detailed explanation-3: -Sori contain 10–13 sporangia interspersed with trichomes and are randomly scattered on the lamina. The annulus is oblique; spores appear to be monolete. Figure 11.192.

Detailed explanation-4: -Dryopteris species can be identified by the circular shaped sori, that is covered by a kidney-shaped, translucent tissue. It is called as indusium. It is a shield like outgrowth of the leaves.