Which of the following is parasitic algae?

a.  Cephaleuros

b.  Harveyella

c. Both A and B

d. None of the above

Chlorophyll pigment is present in all algae, but in many species, the green color is masked by other pigments. Based on the dominant pigments, algae are classified into three groups:

• Green algae – Contain chlorophyll a and chlorophyll b.
• Red algae – Contain phycoerythrin and phycocyanin along with chlorophyll and carotenoids.
• Brown algae – Contain chlorophyll a, chlorophyll c, and the brown pigment fucoxanthin.

Some red algae, such as Harveyella, are heterotrophic and live as parasites on other autotrophic, photosynthetic red algae.

Another example is Cephaleuros, a green parasitic alga that causes red rust of tea. This genus consists of around 14 species, usually about 10 mm in size, with dichotomous branching. Cephaleuros parasitizes several economically important plants including tea, coffee, mango, and guava. Interestingly, some species also form lichens with fungi, though these associations do not harm the host plants.

Thus, Cephaleuros and Harveyella are both well-known examples of parasitic algae.