Step 1: Understanding the Concept:
Antibiotics are chemical substances produced by certain microbes that can kill or inhibit the growth of other disease-causing microbes; several are obtained from fungi.
Step 2: Naming the Species:
Penicillium notatum (and P. chrysogenum) is the fungus that produces Penicillin, the first antibiotic discovered by Alexander Fleming. Cephalosporium species is another fungus used to produce the antibiotic Cephalosporin.
Final Answer:
\(\text{Penicillium and Cephalosporium}\)