152 
Nuclear division 
spindle intranuclear. 
Variations in Glomerella: C. L. SHEAR, U. S. 
Department of Agriculture. 
The results are given of studies of various 
races, strains, varieties and species from forty-six 
different host plants. Variations in morphological 
characters of all kinds were observed. Great vari- 
ations in physiological characters, such as virility, 
adaptability to various hosts and reaction to cul- 
ture media, also ‘occurred. 
Numerous generations started from single asco- 
spores and conidia were grown under the same 
conditions. Rather striking and sudden variations 
occurred in some of these cultures, also inter- 
grading forms and variations appeared. The con- 
idial generations showed greater variation than 
the ascospore generation. Most of the variations 
studied show no direct relation to the culture 
media or other conditions of environment. More 
or less distinct races or strains were found to 
oceur on the same host. These strains maintained 
their principal characteristics in cultures as long 
as they were grown. 
is mitotic with the nuclear 
The Perfect Stage of the Rose Actinonema: F. A. 
Wotr, Alabama Experiment Station. 
The fruit bodies of Actinonema rose are not 
pycnidia as in the Spheropsidales, but acervuli as 
in the Melanconiales. Persoon, who described the 
genus Actinonema (‘‘ Mycol. Hur.,’’ 1822) charac- 
terized it as having radiate, sterile, mycelial 
strands. Fries (‘‘Summa yeg. Scand.,’’ 1849), 
whose characterizations Saccardo employs, de- 
scribes the genus as having a fibrillose radiating 
mycelium, a delicate perithecium and bilocular 
spores. The genus Marsonia, whose conidia are 
similar to Actinonema, has a subepidermal acervu- 
lus. The acervulus of Actinonema rose is sub- 
cuticular. The rose fungus evidently possesses the 
characters of neither a typical Marsonia nor of an 
Actinonema. 
Leaves affected with the conidial stage, when 
wintered out-of-doors, developed a microthyriace- 
ous ascosporic stage. The shield and spores are 
like Asterella. These perithecia though consist of 
a subcuticular shield and an innate apothecium 
which are entirely separate in origin and open 
like the Phecidiales. The Microthyriacee are 
superficial and with a well-developed structure 
only on the wpper side. The type of development 
as exhibited in the rose fungus is not like Aster- 
ella, which has been made to include heterogeneous 
elements and so a new generic name, Diplocarpon, 
SCIENCE 
[N.S. Vou. XXXV. No. 891 
is proposed. This study connects for the first 
time the conidial and ascosporic stages of the 
organism causing the black spot of roses. The 
new name Diplocarpon rose is given to the fungus. 
Infection Experiments with the Powdery Mildew 
of Wheat: GrorGE M. REED, University of Mis- 
souri. 
Experiments have been made in which eighty 
different varieties, belonging to nine different 
species of Triticum, were inoculated with conidia 
of Erysiphe graminis DC. occurring on wheat. 
By far the larger number of these varieties proved 
entirely susceptible to the fungus. Forty-eight 
varieties gave an infection of 100 per cent.; seven- 
teen, an infection of 70 per cent. or higher; four, 
an infection of 50 to 70 per cent.; four, a low 
percentage of infection (4 to 27 per cent.); and 
seven proved practically immune to the mildew. 
In the case of some of the latter varieties an occa- 
sional partial infection was noted. 
The seven immune varieties found belonged to 
two species (Triticum dicoccum and Triticum vul- 
gare), five of these varieties belonging to the 
former and two to the latter species. The emmers, 
as a group, have proved to be quite free from 
infection, although some, as the Winter Emmer 
and Red Emmer, were entirely susceptible. It 
was noted that in every case the varieties which 
proved to be highly resistant to infection are 
spring varieties. 
No one of the nine species of Triticum tested 
proved to be entirely immune. In every case one 
or more varieties belonging to each of the species 
gave infection. 
The Organization of the Hymenium of the Hy- 
menomycetes: A. H. REGINALD BULLER, Uni- 
versity of Manitoba. 
The Nature and Proper Treatment of Lichens: 
Bruce FINK, Miami University. 
An outline of the discussion to appear in the 
second paper of the series on ‘‘The Nature and 
Classification of Lichens’’ now being published in 
Mycologia. A statement of the difficulties due to 
the traditions regarding lichens and the conse- 
quent inconsistent treatment of lichens by many 
botanists. A brief outline of the arguments for 
or against various ideas and hypotheses, especially 
those of de Bary, Schwendener, Reinke, Schneider, 
Peirce, Danilov, Elenkin, Famintzin, Bessey and 
Clements. A conclusion reached as to whether the 
lichen is a colony, a dual organism or a fungus. 
In conclusion, the fundamental problems regarding 
the proper treatment of lichens by morphologists, 
