1925] 



BURT THE THELEPHORACEAE OF NORTH AMERICA. XIV 283 



thin- walled hyphae 1-3 (i in diameter, not incrusted; cystidia 

 thick-walled, with very narrow lumen which is often much larger 

 at apex of cystidium, even where immersed, or sometimes with 

 some granular incrustation near protruding apex, 60-150 X 7- 

 10 (x, protruding up to 50-100 pi, very numerous throughout the 

 fructification, not dissolved by treatment of sections with potas- 

 sium hydrate; spores white, even, cylindric, slightly curved, 

 6-9 X iy 2 -2 n. 



Fructifications 3-15 cm. long, 1-6 cm. wide. 



On wood of decaying conifers, rarely on bark, and on frondose 

 species. In Europe, from Canada to New Jersey, in Nebraska, 

 Colorado, Montana and Manitoba to British Columbia and 

 Oregon. May to November. Common locally. 



P. glebulosa has distinctive cystidia to which Bourdot & Galzin 

 have given the term cystidioles. These cystidia are elongated, 

 cylindric, even throughout their whole length usually, but some- 

 times with a little incrusting matter near the apex of the pro- 

 truding part, and with a very thick wall so thick that the axial 

 lumen containing protoplasmic contents is merely a line which, 

 however, is often greatly expanded at its peripheral end in the 

 apex of the cystidium where the latter becomes thin-walled and 

 fragile. The cystidia of P. glebulosa are not at all dissolved or 

 only partially by the potassium hydrate treatment to which sec- 

 tions are subjected. In the original description Bresadola 

 states that P. glebulosa is the same as authentic Corticium calceum 

 var. glebulosum Fries. I believe this to be an error, for a frag- 

 ment of authentic C. calceum var. glebulosum communicated to 

 me by Bresadola and the original specimens so labelled in Fries 

 Herbarium, all of which I studied, have no cystidia whatever and 

 agree in all respects with a true Corticium collected at Femsjo, 

 the original station, by Romell and myself. 



Specimens examined: 

 Sweden: Femsjo, Romell & Burt, three gatherings; Lappland, 



L. Romell, 405; Stockholm, L. Romell, 199. 

 Austria : Stubai, Tirol, V. Litschauer. 

 Italy : Trient, G. Bresadola, type. 

 England: Symond's Yat, E. M. Wakefield (in Mo. Bbt. Gard. 



Herb., 57120). 



