Question

usually crustose lichens form a pioneen species Give reasons​

Answer 1

Answer:

Crustose lichens form crusts that are so tightly attached to the rocks, trees, sidewalks, or soils they grow on that they can't be removed without damaging the substrate. Foliose lichens are somewhat leaf-like, composed of lobes. They are relatively loosely attached to their substrates, usually by means of rhizines. The species that invade a bare area are called pioneer species. In primary succession on rocks, these are usually crustose lichens which are able to secrete acids to dissolve rock, helping in weathering and soil formation. These later pave way to some very small plants like bryophytes, which are able to take hold in the small amount of soil. They are, with time, succeeded by bigger plants, and after several more stages, ultimately a stable climax forest community is formed. The climax community remains stable as long as the environment remains unchanged.

So, the correct answer is 'Crustose lichen'

Answer 2

Explanation:

Many crustose lichens grow on clean bare rocks and initiate a xerarch succession. Therefore, they are called pioneer plants.

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