Probably, the statutes follow the older definition of fungi as part of the "plant kingdom".
Even so, the FAQ I cited states: "The collection of mushrooms, plants, animals or any natural or cultural item is prohibited." Perhaps you can collect mould if you have a good lawyer.
There was a famous Supreme Court legal decision classifying the tomato as a vegetable (rather than fruit) in tariff law because it was normally consumed like a vegetable, not like an apple.
"Before the introduction of molecular methods for phylogenetic analysis, taxonomists considered fungi to be members of the plant kingdom because of similarities in lifestyle: both fungi and plants are mainly immobile, and have similarities in general morphology and growth habitat. Although inaccurate, the common misconception that fungi are plants persists among the general public due to their historical classification, as well as several similarities." (Wikipedia)
Apparently, the modern taxonomic definition of fungi as a separate kingdom dates back to around 1980.