96 
oF ymenium never labyrinthiform. 
wPileus less than 1 cm. broad; fungus mostly 
resupinate ...........--.ee rere eee IRPEX 
uuPileus more than 1 cm. broad; fungus not 
mostly resupinate............. PoLyPoRuUSs 
b. Hymenium poroid, not broken up into teeth. 
x. Pores large and hexagonal; stipe present. : 
°Stipe lateral, often rudimentary; pores usually radi- 
ating and longer in the radial direction. . FavoLus 
Stipe usually central or sub-central; pores not 
Tadiating cones eas aaa ee Gea reese PoLPpyorRus 
y. Pores small, and circular or angular; stipe present or 
absent. 
°Tubes in a single layer; plants annual. ; 
pTubes not in a distinct stratum but appearing 
to be sunken to different depths into the 
CONLER ty cacao ews eee ashdas ses TRAMETES 
py.Tubes forming a well marked stratum entirely 
distinct from the context..... PoLYPoRuS 
Tubes in two or several layers; plants perennial. 
pHymenium bright yellowish brown; plants 
growing only on the wood of coniferous 
TLEES sc pee ete ae a alae oe ‘TRAMETES 
uuwHymenium whitish, flesh-colored, dull brown, 
etc., but not bright yellowish brown; plants 
growing on the wood of either coniferous or 
deciduous trees...............--- Fomes 
The specimens of polypores, labeled as to name, should next be studied. 
The names of each should be written down, together with an original 
description of the specimen in the student’s own words. These notes should 
be as full as possible, especially as to all the striking differences. 
Life-history. There is great similarity in the life-histories of the poly- 
pores causing wood-rots. Wounds in which the wood is exposed are re- 
quired for infection. The basidiospores, carried by the wind, constitute 
the only kind of inoculum except by the direct growth of the vegetative 
mycelium from a diseased individual to a healthy one. 
Primary Cycles only, exist, since there is only one crop of basidio- 
phores formed annually. A single cycle may require several years to be 
completed. 
Pathogenesis. The spores formed on the basidia are forcibly 
thrown from their sterigmata and fall out from between adjacent projec- 
tions of the hymenial surface (pores or gills). 
Examine figures in Buller, Researches on Fungi, and make diagram- 
matic DRAWINGS illustrating the anatomy of a toad-stool and polypore 
in longitudinal section, showing the path taken by an ejected spore in each. 
The type of infection-court required differs with the species under 
consideration. In general, those fungi causing heart-rots require very 
different types of wounds for successful infection from those causing sap- 
rots. In any case the basidiospore, borne by the wind may find lodgment 
in a suitable infection-court or, if not, it may later be washed by water 
to a suitable place. The spores are relatively short-lived and proper 
conditions for germination must be provided in a short time if the spores 
