Why did Alexander Fleming mark his antibiotic penicillin?

This would be a great help!Why did Alexander Fleming mark his antibiotic penicillin?
He name it that way because of the mold it come from:
He grew a pure culture of the mold and discovered that it was a Penicillium mold, very soon known to be Penicillium chrysogenum. Fleming coined the occupancy "penicillin" to describe the filtrate of a broth culture of the Penicillium mold.
The discovery of penicillin is usually attributed to Scottish scientist Sir Alexander Fleming in 1928, though others have earlier noted the antibacterial effects of Penicillium. Fleming, at his laboratory surrounded by St. Mary's Hospital (now one of Imperial College teaching hospitals) contained by London, noticed a radiance of inhibition of bacterial growth around a contaminant blue-green mold on a Staphylococcus plate culture. Fleming concluded that the mold was releasing a substance that be inhibiting bacterial growth and lysing the bacteria. He grew a pure culture of the mold and discovered that it be a Penicillium mold, now prearranged to be Penicillium chrysogenum. Fleming coined the term "penicillin" to describe the filtrate of a broth culture of the Penicillium mold. Even contained by these early stages, penicillin be found to be most effective against Gram-positive microbes, and ineffective against Gram-negative organisms and fungi