186 BOTANICAL GAZETTE [OCTOBER 
for sporophytes. It was not expected that these terms would 
supplant the more familiar words hermaphroditic and dioecious. 
They may be found useful in bringing about greater accuracy in 
sexual terminology, and in emphasizing the inconsistency of calling 
a form like Marchantia dioecious and a form like the common lily 
hermaphroditic, when the two belong to the same sexual type. 
EVIDENCE FOR SEX INTERGRADES IN HETEROTHALLIC SPECIES 
It is well known that sex intergrades are relatively frequent 
in sporophytic plants like the willow and hemp, which are commonly 
classified as dioecious. Similar sexual abnormalities, therefore, 
have been expected and sought for in heterothallic mucors ever 
since heterothallism was discovered in these forms in 1903. The 
fact that no race of a heterothallic mucor™ has been found by the 
writers which, if it gave any sexual reaction at all, behaved otherwise 
than as a plus or a minus, indicates that sex intergrades in these 
forms are at best extremely rare. It is true that a number of 
investigators have reported findings which they have interpreted as 
opposed to the existence of a strict sexual dimorphism in the bread 
molds and related forms. Despite the fact that their conclusions 
were in harmony with our expectations based upon the condition 
in higher forms, the instances of supposed sex intergrades in hetero- 
thallic species are either isolated observations of two conjugating 
filaments which seem to originate from the same hypha, or have 
been supported by experimental evidence open to criticism. The 
inadequacy of the evidence has been pointed out in earlier publi- 
cations (4, 7, 8), but it seems appropriate to mention two examples 
more or less typical of their kind. The first case is cited by Miss 
McCormick (15), and is illustrated by a figure showing a partially 
matured zygospore with the suspensor on one side arising from a 
filament which curves over and connects with the filament from 
the suspensor on the other side. In reply to an inquiry in regard 
to this zygospore Miss McCormick has written that after the 
* The peculiar homothallic mycelium produced by regeneration of the germ tube _ 
and at times produced from the germination of spores in the germ sporangium in 
Phycomyces (3) is a temporary condition only, and apparently should more properly 
be considered a mixochimera of plus and minus protoplasm, as BurcErFF (13) suggests, 
than as a sexually constant race. 
