4O TROPICAL POLYPORES 



I. MICROPORELLUS DEALBATUS (Berk. & Curt.) Murrill 



Pileus thin, coriaceous, slightly flexible but easily broken, 

 flabelliform or spatulate, conchate, 2-6 X 3-7 X 0.1-0.2 cm.; 

 surface finely tomentose to glabrous, hirtose behind, radiate- 

 striate, dealbate, the zones often light-fulvous; margin very 

 thin, sterile, sericeous, undulate to lobed or cleft, inflexed and 

 often splitting when dry; tubes white to isabelline within, 

 scarcely a mm. in length, mouths minute, angular, 8-10 to a 

 mm., edges thin, entire, glistening, whitish when young, be- 

 coming discolored; stipe variable, often wanting, 0-7 cm. long, 

 2-7 mm. thick, scutate at the base, expanding into the pileus, 

 laterally attached, rarely eccentric, usually compressed, with 

 surface and substance resembling that of the pileus. 



Common throughout on dead wood. The form originally 

 described as P. mutabilis is by far the most common. 



2. MICROPORELLUS UNGUICULARIS (Fries) Murrill 



Pileus thin, coriaceous, reniform or flabelliform, attached by 

 an attenuate base, 2-3 cm. broad, 1-3 mm. thick; surface 

 uniformly ochroleucous, very smooth, concentrically striate, 

 radiate-lineate; margin acute, incurved when dry; context very 

 thin, less than I mm., fibrous, somewhat fragile, watery-white; 

 tubes 0.5-1 mm. long, pallid to yellowish, mouths irregular, 

 angular, 2-4 to a mm., edges white to pallid, thin, fimbriate- 

 dentate, at length lacerate. 



Found once on dead trunks in Mexico. 



3. MICROPORELLUS PORPHYRITIS (Berk.) Murrill 



Pileus thin, coriaceous, flabelliform, 4-5 X 5-6 X 0.1-0.3 cm.; 

 surface pelliculose, ochraceous to light-bay, zonate, glabrous; 

 margin thin, ochraceous, undulate; context fibrous-corky, 1-1.5 

 mm. thick, pallid; tubes short, less than I mm., mouths minute, 

 5-6 to a mm., pallid to discolored, very regular, subangular, 

 edges thin, entire, at first obtuse, becoming acute; stipe variable, 

 short, slightly lighter than the pileus, 5-10 mm. long, 5-8 mm. 

 thick, resembling the pileus in surface and substance. 



Occasional on dead wood in Cuba and western Jamaica, as 

 well as in Brazil. 



4. MICROPORELLUS HOLOTEPHRUS (Berk. & Curt.) Murrill 



Pileus thin, coriaceous, fan-shaped, attenuate behind, laterally 

 attached, 2-5 X 2-6 X o.i cm.; surface conspicuously scabrous, 



