OVERHOLTS: DIAGNOSES OF AMERICAN PortAs—II 249 
trunks on which it grows. I have seen no specimens on trunks 
larger than 3.5 cm. in diameter and the average size is 2—2.5 cm. 
Since it nearly always grows on standing trunks the tubes are 
usually very oblique. In age the hymenium becomes cracked 
(PLATE 14, FIGS. 5, 6), due probably to the shrinkage caused by 
the drying out of the dead stem and by the decay brought on 
by the fungus. The margin of the plant is frequently quite 
irregular in outline or in older plants is apt to become somewhat 
thickened by reason of the receding growth of the fungus. The 
first year’s growth is often not more than a millimeter thick. 
In old dead and dying specimens the margins of the fungus 
loosen somewhat from the substratum. 
The species is one of the easiest of the Porias to identify. It 
is about the only brown species with brown spores, and brown 
spores in all specimens are nearly always to be found in abundance 
inthe hymenium. The lack of setae is also noteworthy in brown 
Porias (PLATE 14, FIG. 7). 
The original deactistion reports the species from Canada, 
Michigan, Nebraska, and Louisiana. In this entire range 
various species of I/ex are present. 
PORIA MEDULLA-PANIS (Pers.) Cooke, Grevillea 14: 
109. 1886 | 
Boltins® medulla-panis Pers: Syn. Method. F ung. 544. 180I!. 
Original Description: (Albus durus) see planus crustaceus, 
superne perforatus; tubulis obliquis (rectisque). 
B. pipet " subterranea. Peet rtim frequens ad ligna 
fabrefacta ex. gr. ianus vetustas, hortorum, aut in sylvis ad 
truncos aridos, inuenitus, oblique glaber, siccus. Pori pro 
loco et situ nuc recti, nunc oblique sunt. 
Redescription: Annual or reviving for several years and event- 
ually as much as 1 cm. thick, broadly effused for many centi- 
meters, inseparable or separating only with difficulty, typically 
with a rather conspicuous pubescent or compactly tomentose 
margin, white t in color: subiculum a thin pallid 
layer that in old specimens resp disappears as such; 
tubes finally indistinctly stratifi fied i ree or four x Aisi or 
alled, 
entire, often oblique, averaging: 3-5 per mm.; spore 
