What type of fungus is known to attack hair?

Microsporum is a type of fungus that is specifically known for its ability to infect hair and skin. It is primarily associated with a group of dermatophytes - fungi that thrive on keratin in hair, skin, and nails. Microsporum species, such as Microsporum canis, are often responsible for conditions like tinea capitis (scalp ringworm), which can lead to hair loss and scaly patches on the scalp.

This fungus forms characteristic structures (macroconidia) that can be observed under the microscope, aiding in diagnosis. It typically infects the outer layer of the hair shaft, causing structural damage and potentially leading to the breakage of hair. The other options, while being fungi, have different typical modes of infection or do not primarily target hair. For instance, Trichophyton is another dermatophyte that can affect hair but has a broader range of infection; Rhizopus is a mold that primarily causes opportunistic infections and does not target hair, and Epidermophyton primarily infects skin and nails rather than hair. Thus, Microsporum is correctly recognized as the fungus known to specifically attack hair.