Rhizopus stolonifer (nigricans). Plus Zygomycete. Black bread mold. Used with minus strain for zygospore demonstration. Maintenance requirements for fungal cultures are similar to those for bacterial cultures. Fungal culture media are typically more acidic and higher in carbohydrates than bacterial media. Allow 5 days for delivery of fungal cultures. Large orders (5 or more) of the same type may require a few extra days.