Many of these species can be detected by direct microscopic exam, but are best identified through culturing the organism. Often the initial growth must be subcultured to a sporulation medium such as cornmeal agar or potato dextrose agar to induce sporulation. Please see the following table for microscopic and macroscopic appearance, as well as other defining features:
| Organism | Clinical Comments | Macroscopic Appearance | Microscopic Appearance | Other Comments |
| Epidermophyton floccosum | Cause of tinea cruris and pedis | Folded, khaki green center with yellow periphery. Reverse yellow/brown with folds. | Large, two to four-celled, club-shaped, multiseptate macroconidia are produced. No microconidia. | Sensitive to cold; don’t refrigerate specimen; can be acquired by shared bath towels. |
Microsporum canis
| Zoonotic; acquired from dogs | Center white to buff, membranous with feathery periphery, yellow periphery. Reverse yellow/orange. (image courtesy of University of Adelaide) | Rough, thick walled, multi-septate, echinulate macroconidia called “aleurioconidia” (detached by the lysis or fracture of the wall of the attachment cell.)
Microconidia are present but rare. | Rapid growing |
| Nannizzia gypsea (previously known as Microsporum gypseum) | Free-living in soil | Cinnamon color and powdery; reverse light tan. | Rough, thick, multi-septate, spindle shape macroconidia. Rare microconidia.  . | Rapid growing. Usually acquired from the soil, not other humans. |
Trichophyton mentagrophytes
| Common isolate | Vary from white granular to fluffy; reverse buff or reddish brown. | Round microconidia usually in grape-like clusters. Thin walled, club shaped macroconidia. | Urease- positive |
Trichophyton tonsurans
| Cause of epidemic tinea capitis | White-tan-rust suede-like or powdery. Reverse yellow to tan or rust-red. | Microconidia tear drop or club shaped with flat bottoms. Macroconidia are rare. | Slow growing |
Trichophyton verrucosum
| Often acquired from cattle | White velvety with rugal folds. | Chlamydoconidia in chains; microconidia are teardrop shape but rare. | Slow growing |
Trichophyton rubrum
| Common isolate; cause of feet & nail infection (Tinea Pedis) | White/pink; rugal folds. Reverse side becomes wine or red color with age. | Tiny microconidia along sides of hyphae. Resemble “birds on a fence”: Macroconidia usually absent | Slow growing Urease- negative |
