Although there are many types of molds, only a few dozen cause allergic reactions. Alternaria, Cladosporium (Hormodendrum), Aspergillus, Penicillium, Helmin thosporium, Epicoccum, Fusarium, Mucor, Rhizopus and Aureobasidium (Pullularia) are the major culprits. Some common spores can be identified when viewed under a microscope. Some form recognizable growth or colonies.
Asthma & Allergy Foundation of America