*Solutions* ✅ In invasive aspergillosis, Aspergillus forms fruiting bodies (usually in lung cavities) and septate filaments, 5 to 10 μm thick, branching at acute angles (40 degrees). Aspergillus is a ubiquitous mold that causes allergies (allergic bronchopulmonary aspergillosis) in otherwise healthy people and serious sinusitis, pneumonia, and invasive disease in immunocompromised individuals.