60 College of Forestry 
ally shorter, and less enlarged at the tip. The latter ele- 
ment corresponds to what has been termed paraphyses in 
the Hymenomycetes. According to Curtis (1914) the 
so-called paraphyses of the Agaricales are nothing more 
than potential basidia and continue to develop as such dur- 
ing the life of the fungus. It is more reasonable to regard 
these organs as potential basidia than as inert structures 
which serve only as reinforcing or spacial agents, as some 
have viewed them. Owing to the leathery nature of such 
a fungus as Polyporus pargamenus the necessity for special 
agents or reinforcing structures is precluded. These organs, 
under favorable conditions, undoubtedly are capable of> 
developing into mature, spore-producing basidia. This 
view is supported by reason of the fact that spore forma- 
tion continues for a long period, and careful examination 
of sporophores of various ages has shown that the spores 
produced by a basidium mature at approximately the same 
time. The spores, however, are shed intermittently over long 
periods, and from this fact it follows that the basidia prob- 
ably develop successively during moist periods, a cireum- 
stanee which would account for the continued spore forma- 
tion. The examé‘nation of sections of sporophores developed 
in a moist chamber likewise gives evidence that the basidia 
mature successively. This view is further supported by the 
faet that sporophores sometimes revive and produce a new 
hymenium the second year due to accelerated growth of cer- 
tain hyphee in the hymenial layer 
The basidia are more or less regularly disposed throughout 
the hymenium. On the enlarged end of each basidium are 
four minute spine-like sterigmata, each of which bears a 
basidiospore. Scattered irregul: arly among the basidia there 
sometimes occur conspicuous, blunt cystidia usually capitate 
with an incrustation of mineral matter. 
Cystidia may be defined as the more or less conspicuous 
sterile organs found either in the hymenium or in the sub- 
hymenial tissue of various basidiomyeetous fungi. They 
are the modified ends of some of the tramal hyphee which 
extend into the hymenial layer and usually project beyond 
