The mycelial form of which dimorphic mold produces thick-walled, rectangular, or barrel-shaped alternate arthroconidia?

The mycelial form of Coccidioides immitis is characterized by the production of thick-walled, rectangular or barrel-shaped arthroconidia, which are a key feature of its morphology. In the soil, C. immitis can produce these arthroconidia as part of its asexual reproduction, and they can survive in harsh environmental conditions. When the mold is inhaled, the body temperature promotes the transformation into its yeast form, which is a crucial aspect of its dimorphic nature.

Understanding this morphology is vital for identifying C. immitis in laboratory settings and is part of the identification process for this pathogen, which can cause coccidioidomycosis, a respiratory disease. The other molds listed, such as Sporothrix schenckii and Histoplasma capsulatum, have distinct forms and reproductive structures that differ significantly from those of C. immitis, making it essential to recognize and differentiate these characteristics in clinical microbiology.