1920] 



BURT — THELEPHORACEAE OF NORTH AMERICA. XII 125 



upper side villose-tomentose, light buff to cartridge-buff, the 

 margin entire; hymenium even, glabrous, light purple-drab to 

 dark vinaceous-drab; in structure about 500-800 ix thick ex- 

 cluding the tomentum, with the intermediate layer more loosely 

 arranged on its under side in the 

 subhymenial region and contain- ^. r ••rnrf vtt 

 ing pyriform, or subglobose, vesic- \\\ iijj/li'Wj ill I 

 ular organs 15-30X12-25 n; no U/^hp J ^i^'///-^ 



^^/^ 



cystidia; spores hyaline, even, •^^^-^^^^ 

 flattened on one side, 5-7X2§-3 y.. 



Fructifications with resupinate ~^^^=^^==~ 

 portion about 1-2 cm. in diam- 

 eter; reflexed portion 5-20 mm. ^ig- 13. 'Sf. pwpweum. Section 



,1 T , . . 1 of hymenial region X 90, and vesic- 



broad, and sometimes crisped ^i^r bodies X 665. From authentic 



or lobed with lobes 5 mm. in specimen. 

 diameter. 



On dead stumps and logs of Populus, Betula, and other fron- 

 dose species. Newfoundland to Delaware and westward to 

 British Columbia and Oregon, also in Uruguay and in Europe. 

 June to April. Common but not ranging into torrid regions. 



S. purpureum is usually recognized by its buff, tomentose 

 pileus, purplish hymenium which does not bleed when wounded, 

 and occurrence on poplar. Sectional preparations show charac- 

 teristic vesicular organs in the subhymenial region, such as 

 are present in the closely related S. rugosiusculum, but no hair- 

 like cystidia in the hymenium, by the absence of which S. pur- 

 pureum is distinguished from the latter. 



The authentic specimen of S. vorticosum in Herb. Fries at 

 Upsala is 2-3X1^ cm., narrowly reflexed, with dark purplish 

 hymenium, and with the usual microscopic structure and spores 

 of S. purpureum. 



Specimens examined: 

 Exsiccati: Bartholomew, Fungi Col., 3489; Berkeley, Brit. 

 Fungi, 147; Cooke, Fungi Brit., 12; Ell. & Ev., N. Am. 

 Fungi, 2018, 2601; Klotzsch, Fungi Germ., 50; Krieger, 

 Fungi Sax., 1852; Rabenhorst, Herb. Myc, 504; Romell, 

 Fungi Scand. Exs., 27; Shear, N. Y. Fungi, 311. 

 Europe: authentic specimen of Thelephora purpurea from Per- 

 soon (in Herb. Hooker in Kew Herb.). 



