162 BOTANICAL GAZETTE [SEPTEMBER 
obligate parasite upon various mucors, he found would grow on 
Cunninghamella as host, but on none of a considerable number oi 
non-mucor forms from representative groups of the higher and lower 
fungi. From the results of this ingenious test of parasitism, and 
from the vegetative structure, he decided that Cunninghamella was 
to be placed in a distinct group of the Mucorineae alongside of 
Choanephora, where Oedocephalum-like fructifications occur in 
addition to sporangia. The discovery of the zygospores of this 
species by the writer? has established beyond question its position 
among the Mucorineae, and renders not improbable that a further 
cultural investigation may similarly give independence to others of 
the Fungi imperjecti. Since the method of finding the sexual fom 
of reproduction in this species is that which recently the writer has 
adopted in obtaining, among others, the zygospores of Seyncephal- 
astrum, Absidia repens, Helicostylum, and Circinella umbellata, for 
which, with the exception of the last species, zygospores had never 
been known, it seems not inappropriate to give a brief account of 
their discovery in Cunninghamella. It is believed, moreover, that 
an application of similar methods may lead to a clearing up of some 
of the present anomalies in fruit production encountered in other of 
the fungi as well as in the algae. 
According to their method of sexual reproduction, the Mucorineat 
have been divided into two main groups, homothallic and heter0- 
thallic, characterized respectively by bisexual and unisexual thallt’ 
In the forms known to belong to the homothallic group, zygospors 
are produced along with the non-sexual sporangial spores under 
normal cultural conditions, and for this reason the majority of them 
have been kept under cultivation with a constant production of zy” 
spores for many years. No new members have been added = a 
group during the present year’s investigation, while the pee 
a number of forms to the heterothallic group further emphasize*" 
conclusion that this latter group comprises a very large majon'y 
the species. The (+) and (—) sexual strains of heterothallic oe 
were first obtained analytically from those few fortunate cu 
2 Sexual reproduction in the Mucorineae. Proc. Am. Acad. 40:31% 1904 $66. 
3 Loc. cit. and Zygospore formation a sexual process. Science N. S. 19° 
1904. 
