JANUARY 26, 1912] 
were obtained from freshly gathered material of 
Gymnosporangium, Peridermium and Acidium, 
out of 91 sowings. 
The most important results of the year were 
(1) finding an ecial host for Gymnosporangium 
speciosum outside of the families Malacee and 
Rosacer, %. e., on Philadelphus, belonging to the 
family Hydrangiacee, and (2) finding that both 
the Uromyces and Puccinia on Distichlis spicata 
produce indistinguishable ecia on the same xcial 
hosts. The latter result taken in connection with 
facts brought out in former culture work leads to 
the conclusion that in some eases at least forms 
placed in the two genera, Uromyces and Puecinia, 
are not worthy of generic difference, and scarcely 
entitled to specific difference. They more truly 
represent races, or possibly varieties, of one spe- 
cies, rather than two species belonging to two 
genera. 
Plus and Minus Strains in an Ascomycete: C. W. 
EpeGerron, Louisiana Experiment Station. 
A species of Glomerella collected on a petiole of 
a cottonwood leaf in Louisiana has been producing 
perithecia on culture media for nearly a year and 
a half. The original culture has been separated 
into two distinct strains, called Plus and Minus. 
The Plus strain develops mature perithecia in 
masses occasionally, these being identical with 
other species of Glomerella. The Minus strain 
develops the perithecia singly or in two’s or 
three’s over and in the medium, but these do not 
come to maturity except on certain media and 
then the asci are very ill-shaped. When the two 
strains are grown on the same plate, there is a 
boundary line, where they come in contact, of 
well-developed perithecia. There is a cross-fer- 
tilization between the two strains, as is shown by 
the fact that ascospores in the same perithecium 
develop both strains on culturing. 
The Morphology of Zygorhyncus and its Relation 
to the Ascomycetes: GEO. FE. ATKINSON, Cornell 
University. 
In Zygorhyncus the fruiting hyphe are aerial 
and arise from the submersed vegetative mycelium. 
The branching is sympodial, the first sporangium 
terminating the primary hypha, the system finally 
bearing several sporangia, the successive ones 
usually standing higher. The sporangial branches 
are often more or less spirally curved. 
The branched gametophore is the morphological 
equivalent of the sporangiophore, and the sexual 
branches are morphologically equivalent to the 
sporangial branches, and arise according to the 
SCIENCE 
151 
same plan. The gametophores and sporangio- 
phores are usually pure, but sometimes mixed. 
The first antheridial branch is terminal, and 
subtended by the oogonial branch. The latter 
curves around, is often spirally twisted, and comes 
in contact with the former, usually touching it on 
the side. The end of the oogonial branch then 
enlarges into an oval body and is divided by two 
eross walls. The terminal pointed cell in contact 
with the antheridium is the homologue of the 
ascomycete trichogyne, and the subterminal cell 
is the egg. The ‘‘zygospore’’ wall eventually 
ineludes the two cells. 
The sexual apparatus of Zygorhyncus is of the 
same type, and may be regarded as representing 
the ancestral form of the same, in Monascus, Gym- 
noascus, Pyronema, ete., and the gametophore may 
be regarded as representing the ancestral form of 
the Laboulbeniales. It does not seem necessary, 
therefore, to derive the ascomycete thrichogyne 
from the Rhodophycee. 
Development and Fertilization in Olpidiopsis: J. 
F. Barrett, University of Illinois. 
Three species of Olpidiopsis were included in 
this study: O. Saprolegnie Cornu, on Saprolegnia ; 
O. vexans nov. sp., on Saprolegnia, and O. lua- 
urians nov. sp., on Aphanomyces. 
Zoospores biciliate with the cilia of equal length 
and attached at or near the anterior end of the 
elongated body. Zoospores possess two motile 
stages separated by a brief period of rest, sug- 
gesting a primitive type of diplanetism. Indi- 
viduality of the zoospore, after penetrating the 
host, is maintained throughout its development. 
Little if any ameboid movement. 
Segmentation of the sporangial contents appar- 
ently simultaneous throughout. Zoospores on es- 
caping contain vacuoles. 
True sexuality probably exists, and takes place 
by the fusion of two sexually differentiated indi- 
viduals and the subsequent passage of the proto- 
plasm of the smaller, male, into the larger, female, 
cell. This is followed by a supposed fusion of 
nuclei. 
Both sexual and asexual reproductive bodies 
develop rather rapidly from a uninucleate to a 
multinucleate condition. The oospore is likewise 
multinucleate. 
External conditions play a great part in the 
determination of sex in these organisms. This 
fact adds evidence, it seems, to the doctrine that 
sex in many plants is determinable by external or 
nutritive conditions. 
