Polyporus calkinsii (Murrill) Sacc. & Trotter 1912

Tyromyces calkinsii Murrill, sp. nov
Pileus sessile, somewhat imbricate, dimidiate, convex above, concave below, cheesy when fresh, rigid when dry, 3-5 X 6-8 X l. 5-2 cm.; surface smooth, glabrous, azonate, white to cremeous or ochraceous-fulvous ; margin thin or thick, entire or undulate, easily bruised, fertile : context white, homogeneous, fleshy to somewhat friable, very firm, 5-10 mm. thick; tubes slender, white to ochraceous within, equaling the thickness of the context, mouths regular, angular, 3-4 to a mm., firm, white to yellowish and finally avellaneous, edges thin, entire to slightly dentate: spores globose, smooth, hyaline, 5/^;
hyphae 1 }i ; cystidia none.
Type collected in Florida, on dead wood, December, 1886, W. W. Calkins 619. Distribution : Florida.

Tyromyces calkinsii is a plant pathogen infecting sweetgums.