252 OVERHOLTS: DIAGNOSES OF AMERICAN PoriAs—II 
I am at present inclined tothat opinion, but to admit these plants 
would extend the host range of this species to include wood of at 
least the main coniferous trees and give a gradation into typical 
P. subacida that would be extremely confusing. Yet in view of 
the close similarity in microscopic characters it might simplify 
matters to refer all these plants to such a one protean species. 
STATE COLLEGE, PENNSYLVANIA 
Explanation of plates 13 and 13 
he kee te in this paper are from free hand sections cut by the 
writer from herbar specimens and mounted in glycerine. I have had the 
assistance of Mr. P. F. Shope in the preparation of the illustrations. 
PLATE 13 
PoRIA CORTICOLA (Fr.) Cooke 
FIG. I. Photograph, x 1%. Overholts Herbarium, No, 502 
“Fic. 3.. Photomicrograph of cross section of hymenium of Swedish 
specimens, showing the angular pores and the distribution of the cystidia, 
Fic. 4. Photomicrograph of same specimen showing a cluster of cys- 
iia, XX 430) 
F . Closest approach in American specimens to the cystidial con- 
dition of European P. corticola. Cystidia represented at a, b, c, and d 
Overholts Herbarium, Sur 5912. 
: Fic. 6. Photomicrograph, X 320, showing the small capitate incrusted 
Sages that project ak slightly beyond the basidia. Overholts Herbarium, 
No. 8019. 
Fic. 7. Photomicrograph, X 320, showing a somewhat more heavily 
incrusted cystidium sometimes present. Overholts cartes No. 4211 
PLATE 14 
Fics. 1-4. PorIA MEDULLA-PANIS (Pers.) Cooke 
Fic. 1. Photograph, X 1%, of a specimen of the more flabby and 
coriaceous type of this species. Overholts Herbarium, No. 5682. 
Fic. Photograph, 114, showing the harder, more sg and 
ears Sapien type of the species. Overholts Herbarium, No. 
Photomicrograph, XX 160, of cross section of the tras 
Overholt Hevharlens: No. 
pescrograph, % 320, showing small portion of the hymenial 
wees = the same ple 
