The lichen commonly known as the 'reindeer moss' is
(a) Marsilea
(b) Cladonia
(c) Georgia
(d) Usnea

Options

A. Marselia
B. Cladonia
C. Georgia
D. Usnea

Answer

To solve the question regarding which lichen is commonly known as 'reindeer moss', we will analyze each option provided:

1. **Option (a): Marsilea**
- Marsilea is commonly known as water clover. It is a type of aquatic plant and not a lichen. Therefore, this option is incorrect.

2. **Option (b): Cladonia**
- Cladonia is indeed known as reindeer moss. It is a lichen that thrives in arctic regions and is commonly found in the tundra and taiga ecosystems. This option is correct.

3. **Option (c): Georgia**
- The term 'Georgia' refers to Spanish moss, which is not a lichen but rather an epiphytic plant. This option is incorrect.

4. **Option (d): Usnea**
- Usnea is commonly known as beard lichen or string of sausage lichen. It is also not known as reindeer moss. Therefore, this option is incorrect.

After evaluating all the options, the correct answer is:

**(b) Cladonia**