





1891.] _ Ihe Comparative Morphology of the Fungi. 1065 
as those of the latter group, although they germinate differently. 
Like those of the Ustilaginez, its spores, as ordinarily observed, 
must be regarded as chlamydospores, and, like most of those, 
their germination is fructificative; but the product of germination 
is a sporangium which shows a tendency towards the more defi- 
nite form of the ascus. In this view Brefeld adopts the early 
explanation of DeBary, the first student of the genus, which was 
afterwards reconsidered by him. These three intermediate forms 
hold the same relations to the Ascomycetes as do the Ustilagi- 
nez to the Basidiomycetes, and similarly they are grouped 
together under the name Hemiasci; Ascoidea and Protomyces, 
with naked sporangia, constitute the Exohemiasci; and Thele- 
bolus, with its well-developed fruit body, is the type of the Car- 
pohemiasci. ‘Fhese two intermediate groups, the Hemiasci and 
the Hemibasidii, are made to constitute, under the name Meso- 
mycetes, one of the three great divisions of the fungi, coordinate - 
with the Phycomycetes and the Mycomycetes. This last group 
includes the true Basidiomycetes and Ascomycetes, the “ higher 
ungi,” 
Of the accessory fruit forms, chlamydospores are not common 
among the Ascomycetes, though both Oidia and the typical form 
may occur. Unquestionable specimens of the latter are known in 
the Sepedonium and Mycogone stages of those parasites of “ toad- 
stools ” and similar fungi which belong to the genus Hypomyces. 
While, theoretically, there is no reason why unmodified sporangia 
or conidiophores modified into basidia should not occur as acces- 
sory forms in the Ascomycetes, they have, in fact, never been 
observed; but the ordinary conidiophores are very abundant,— 
much more so than in the Basidiomycetes. These may arise from 
retrograde development of sporangia still left after the differentia- 
tion of the asci; or they may represent the conidia of 
Choanephora-like forms whose sporangia have become asci. 
They are formed either by budding from the ascospores at ger- 
mination, after or even before their escape from the ascus; by 
abstriction from the germ-tube directly; or on distinct conidio- 
phores. The budding of conidia from the ascospore recalls the 
similar cases among the lower Basidiomycetes; but it may be 


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