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differentiated, stolon-like threads, which arise from the ordinary 
mycelium. 
The higher fungi, i. e., the most highly developed, consist of the 
Ascomycetes and Basidiomycetes, or so-called Mycomycetes, and the 
intermediate Hemiasci and Hemibasidia, the so-called Mesomycetes, 
connecting the higher fungi with the Phycomycetes. The sexual organs, 
which are destitute of function in some of the Oomycetes and still 
further degraded in Zygomycetes, disappear altogether in the higher 
fungi and are not found even in a rudimentary state, whereas nonsex- 
ual methods of reproduction take on a compensating multiplicity of 
forms. Originally the nonsexual form was a sporangium, as in Mucor 
mucedo , and its change into a spore (conidium) can be followed step by 
step through the Thamnidhe and Chgetocladiacese. In the Choaneplio- 
rem the conidia are still accompanied by the sporangia, but in the Chm- 
tocladiacem the latter have disappeared, and it is precisely from this group 
of Zygomycetes that the Basidiomycetes appear to have arisen. From 
this poiut of view there are three types of Zygomycetes: (1) Forms 
with sporangia only, (2) forms with sporangia and conidia, (3) forms 
with conidia only. Among the sporangial forms, moreover, Mortierella 
rostafinshii shows a distinct advance into a sporangial fruit, the begin¬ 
ning of which may be seen even in Rhizopem. Finally, in Ghlamydo- 
mucor racemosus there has developed an additional, purely accessory 
spore, thechlamydospore, which occurs either as a chlamydospore proper 
or simply as an oidium. As already stated, all of these nonsexual 
spore forms, sporangial, conidial, and chlamydosporous, occur in great 
variety in the higher fungi. In the Hemiasci and Ascomycetes we have 
forms which fructify in sporangia only, or by sporangia and conidia, 
and these may be designated the sporangial series of the higher fungi. 
On the contrary, in the Hemibasidia and the Basidiomycetes there are 
no sporangia, but only conidia. These fungi evidently had their origin 
in the Zygomycetous Chmtocladiacese and may be designated the 
conidial series of the higher fungi. Ohlamydospores occur in both, 
and both sporangia and conidia are modified and specialized. The spo¬ 
rangium in Zygomycetes varies as to form, size, and number of its spores 
in the same species, but in the higher fungi definiteness becomes more 
and more pronounced until in Ascomycetes the sporangium becomes an 
ascushaving a determinate shape and bearing adefinite numberof spores. 
In these particulars the Hemiasci form a transition group, their spo¬ 
rangial fructification being ascus-like, but more variable than in Ascomy¬ 
cetes. In the conidial series it is the conidiophore which has become 
specially developed. In Zygomycetes also the conidiophore varies in 
form, size, and number of its spores. In the Basidiomycetes it has 
been specialized into a basidum of definite form and bearing a definite 
number of spores. Here, again, there is an intermediate group, the 
Hemibasidia, connecting the basidia-bearing forms with the much 
simpler Zygomycetes. The accessory spore form, i. e., the chlamydo- 
