NATURAL HISTORY SURVEY 117 



POLYSTICTUS. 



Pileus coriaceous, membranaceous or fibrillose; pores evolved 

 successively from the center toward the margin, at first superficial, 

 punctiform, discrete, open, then more deeply excavated, crowded, 

 always vertically opposed to the substance of the pileus. Trama 

 formed by the hymenophore. Lignatile or terrestrial. 



1 . With a stem P. cinnamomeus. 



1. Sessile 2 



2. Pileus glabrous 3 



2. Pileus velvety or hirsute 4 



3. Pileus whitish, with darker zones, pores 



pallid P. conchifer. 



3. Pileus and pores cinnabar-red P. cinnabarinus. 



4. Pileus white, pores violet becoming pale. . P. pergamsnus. 



4. Pileus whitish or grayish 5 



4. Pileus dark, with zones of various colors, 



pores white then pallid P. versicolor. 



5. Pileus silky-fibrillose, becoming alutaceous, 



pores concolorous P. biformis. 



5. Pileus shaggy with rigid hairs, pores whitish 



then yellowish P. hirsutus. 



Polystictus cinnamomeus Jacq. 



Wholly bright cinnamon without and within; hymenium 

 paler. 



Stem velutine-tomentose, 3 to 4 cm. long, 4 to 5 mm. thick. 



The pileus is piano-depressed or subinfundibuliform, 2 to 3 

 cm. broad, zonate; the margin often remarkably fimbriate; hy- 

 menium sterile toward the margin. 



Pores large, angular; spores ellipsoidal, 6 to 7 x 4 to 5 /*. 



Common in wooded sand dunes at the head of Lake Michigan. 

 When old, the pileus becomes ashy-gray, beautifully marked with 

 narrow, darker, concentric zones. Single plants are commonly 

 1.5 to 2.5 cm. in diameter, but by confluence of two individuals 

 the pileus may be twice as broad. Specimens occasionally occur 

 which, though similar in other respects, have smaller pores. 

 These possibly are the form which has been described by Berkeley 

 as P. oblectans, and by Prof. Peck as P. subsericeus and P. simil- 

 limus. The mode of attachment of the pores to the stem is not 

 constant. In a series of plants some may be found with the pores 

 scarcely more than adnate, while others have them decurrent on 

 one side of the stem, and still others evenly decurrent all around 

 the stem. 



Polystictus conchifer Schw. (Plate XVI, Fig. 2. 



Whitish; pileus coriaceous, very thin, concentrically sulcate, 

 glabrous, commonly reniform or flabelliform and substipitate. 



Pores medium, thin, acute, angulate, dentate, but scarcely 

 lacerate. 



