Question

The common inter-cellular parasitic algae among the following is:

• A. Cladophora
• B. Chlamydomonas chrenbergii
• C. Cephaleuros
• D. Protoderma

Hint:

The association of {Cephaleuros} with the disease "red rust" on tea plants is a classic example of algal parasitism taught in botany. Remembering this specific example can help you quickly answer such questions.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
The question asks to identify a genus of algae that is known to be parasitic and grows inter-cellularly (between the cells) within a host plant.
Step 2: Detailed Explanation:
Let's examine the lifestyles of the given algae:

(A) {Cladophora:} A genus of filamentous green algae that is typically free-living in freshwater or marine environments. It is not parasitic.
(B) {Chlamydomonas chrenbergii:} A species of unicellular, motile green alga. It is free-living, commonly found in soil and freshwater. It is not parasitic.
(C) {Cephaleuros:} This is a well-known genus of parasitic green algae. Species like {Cephaleuros virescens} grow on the leaves of terrestrial plants (e.g., tea, coffee, mango) and cause a disease commonly called "red rust". The algal filaments grow in the subcuticular and inter-cellular spaces of the host leaf.
(D) {Protoderma:} This is a genus of green algae that grows as a crust on various substrates like rocks or other plants (epilithic or epiphytic). It is not considered a parasite.
Step 3: Final Answer:
{Cephaleuros} is the common example of an inter-cellular parasitic alga among the given options.