86 EVOLUTION OF PLANTS 
(Mucorini) may have originated from algz like the 
Conjugate, just as the water-moulds are supposed to 
have originated 
from green forms 
resembling Vau- 
cheria; but the 
structure of the 
thallus and the 
/ non-sexual spores 
of the black- 
moulds are so 
very _ different 
from those of the 
Conjugatee that it 
Fig. 22 (Phycomycetes).— A, a plant of a com- 
mon eae ous (Mucor stolonifer), ie seems much more 
groups of stalked sporangia, sp, arising from : 
ue oreping. ener thizoids, or root- likely that the 
ets; B, young; C, mature sporangium seen $a eas . 
in optical section, showing the columella, similarity in the 
col.; D-F, successive stages in the develop- sexual cells is 
ment of the sexual spore or zygospore. 
D 
purelyaccidental. 
At any rate these fungi and their near relatives the 
insect-fungi (Entomophthoracez) must be regarded as 
much further removed from the alge than the water- 
moulds and white-rusts with their ciliated zodspores, and 
distinct odgonia and antheridia. 
THE MycomMycetses 
Most of the Fungi differ in structure so widely from 
the green plants that it is difficult to find any points of 
resemblance. These typical Fungi or Mycomycetes 
differ in nearly all respects from other plants, both in 
their structure and their methods of reproduction. 
