| Kingdom: Fungi | 
| Phylum: Ascomycota | 
| Subphylum: Pezizomycotina | 
| Class: Sordariomycetes | 
| Subclass: Sordariomycetidae | 
| Order: Ophiostomatales | 
| Family: Ophiostomataceae | 
| Genus: Ophiostoma | 
| Subject: Ophiostoma ulmi (Buisman) Nannf. | 
| Kingdom: Plantae | 
| Phylum: Magnoliophyta | 
| Class: Magnoliopsida | 
| Subclass: Hamamelidae | 
| Order: Urticales | 
| Family: Ulmaceae | 
| Genus: Ulmus | 
| Subject: Ulmus americana L. |