Genus species: Penicillium chrysogenum

Series: Celebrate the Century -1940s (United States 1999)
Catalog codes:
- Michel: US 3076
- Stamp Number: US 3186b
- Yvert et Tellier: US 2839
- Stanley Gibbons: US 3551
Emmission: Commemorative
Perforation: 11½
Printing: Offset lithography
Colors: Multicolor
Face value: 33¢ - United States cent
Print run: 12,500,000

This is the first US postage stamp issued with a fungus as the main illustration. It’s an SEM (scanning electron microscope) view of conidiophores with conidia (Penicillium sp.) and is artificially colored blue-green to look like the growing mold.

Reference: www.psms.org, colnect.com
Shop now link: ebay.com (note: market availability)