750 The American Naturalist. [August, 
peach the stem infection takes place apparently only through the blos- 
soms or fruits, and here apparently only through the leaves. The 
striking similarity may be seen by comparing Woronin’s Fig. 23, Table 
II, with Journal of Mycology, Vol. VII, Plate V, figs. 1, 2 and 3. 
The germ tubes bore directly through the epidermal cells of the host or 
penetrate at the junction of two or more cells. In no case were they 
found entering through stomata, although most of the infections were 
through the underside of the leaf. On culture media long chains of 
conidia develop before any septa appear. Finally the ripe conidia are 
separated by delicate spindle-form or diamond-shaped disjunctors con- 
sisting of two minute cones of cellulose joined at their bases and having 
their apices connected with the two adjacent spores. Neighboring 
ascospores and conidia as well as germ tubes often fuse, and this is very 
striking in case of the infection of the incipient fruit through the 
stigma. For this purpose a half dozen conidia may fuse into a sort of 
colony or association giving rise to a single, very robust hypha which 
grows down the style after the manner of a pollen tube and finally in- 
fects the ovary. Fusions of spores and of hyphae are common enough 
in fungi, but fusion for so manifest and important an end is certainly 
noteworthy. The elongated penetrating hypha usually remains un- 
branched until the ovary is reached. In 3—4 days from the time of 
placing the spores on the stigma the germ tube has reached and entered 
the micropyle, and a day or two later the nucellus is invaded. No 
further development of the fungus takes place unless the flower has 
been fertilized by a pollen tube. In that case there is a movement of 
nutrient substances into the ovary, and on these the fungus makes a 
luxuriant growth. First the nucellus is occupied, then the integuments 
are invaded, and finally the pericarp, following which the young fruit 
browns externally and shrivels, and, if the air is moist enough, conidia 
appear on its surface. During early stages of germination 4-10 prob- 
lematic bodies resembling nuclei appeared pretty constantly in each 
germ tube and then disappeared. The fungus on mountain ash is 
smaller than S. padi, but is otherwise very similar. The paper closes 
with 5 pages on relationships among Sclerotinia ——Erwin F. SMITH. 
Demonstration of Photosyntax by Bacteria.—In Verhan- 
delingen d. Koninklijke Akad. van Wetenschappen te Amsterdam (2 
Sectie, Deel III, No. 11) Professor Th. W. Engelmann summarizes in 
a brief paper (Die Erscheinungsweise der Sauerstoff: heidung chro- 
mophyllhaltiger Zellen im Licht bei Anwendung der Bacterienmethode) 
what is known on this subject, and illustrates it very satisfactorily by 
