Question

Which of the following is an example of reed swamp stage during hydrosere-?
A. Cyanobacteria
B. Vallisneria
C. Azolia
D. Typha

Answer 1

Hint: In reed swamp stage, emerging species surround the reservoir to create a reed-swamp. These plants have growing rhizomes that knead the mud together and create vast volumes of leaf litter. This litter is immune to decay and is made up by reed peat, speeding the autogenic transition.

Complete answer
First we should know about hydrosere to answer this question. A hydrosere is a succession of plants that occurs in a freshwater environment including in kettle lakes and oxbow lakes. Over time, an open moist environment would gradually dry out and finally become woodland. A number of distinct landforms, like swamp and marsh, will support one another throughout this change.
 Now, let us find the solution from the options-
->Hydrosere is the reproduction of plants in the freshwater environments.
- >There are many steps. The reed swamp stage is the hydrosere stage where the plant roots are immersed in the water while the above portion is aerial or floats on the water surface.
->There are also examples of swamping reeds i.e. Nymphaea, grasses in reeds etc.

Thus, the correct option is option (D) i.e. Typha

Note: The early shifts are allogenic as inorganic particles like sand and clay are swept from catchment areas and continue to fill the water body's basin. Subsequently, remnants of dead plants still occupy certain bodies and lead to further environmental changes.