Life history of a new species of Sphaerella 189 
without several dead spots and they began to turn yellow and drop off 
during August. 
On Sept. 4 th some of these fallen leaves contained small black bodies 
in the spots which had been killed by the Septoria. Ten days later these 
spots were densely dotted with these bodies which were conspicuous be¬ 
cause of their black color on the yellow or yellowish brown leaf tissue. 
Spots on many of the yellowed leaves which were still on the trees also 
showed these bodies. 
Freehand sections showed two kinds of structures. One had the 
appearance of a small stroma and the other that of a pycnidium contain¬ 
ing very small rod-like spores. These last were thought at the time to 
belong to a saprophytic Phyllosticta , and because of the rush of other 
work were not studied carefully at that time. Some of the leaf tissue 
containing these structures was killed on Sept. 4 th , Sept. 14 th , and again 
on Dec. 18 th and embedded in paraffin for further study. 
When this material was sectioned and stained, the small spores 
were found very often forming in the same pycnidium where the typical 
Septoria spores had been produced, which indicated that they were geneti¬ 
cally connected with the Septoria. They are formed on slender sterigma- 
Kke projections arising from the large deeply staining cells which line the 
pycnidium at this time. These cells often grow out in chain like branches 
which reach entirely across the pycnidial cavity. 
The stroma-like bodies mentioned above were found to be young 
perithecia. The wall of the perithecium develops in manner very similar 
to that described for the pycnidium; but they form deeper in the tissue 
of the leaf, usually in the palisade layer or sometimes in the mesophyll on 
the underside of the leaf. A dense hyphal knot arises by the branching 
of one or more hyphae. These branches soon coalesce and form the 
pseudoparenchymatous wall of the perithecium. The neck of the peri¬ 
thecium is finally formed by coalescence of the more or less spirally wound 
ends of these branches. 
Very early in the formation of the young perithecium from the 
hyphal knot, a deeply staining central branch is differentiated. The base 
of this hypha is enlarged and once or twice coiled, and the free end of 
the coil extends as a slender trichogyne-like structure. It reaches to the 
ostiolum but has not been seen projecting beyond. These structures aie 
very similar to the carpogonial structures found by Frank 1 ) in Gnomonia 
erythrostoma and by Fisch 2 ) in Polystigma rubrum. 
The small pycnospores, from their size, mode, and time of formation 
are probably homologous with what has been termed spermatia. No evi¬ 
dence that they function as male sexual organs has so far been found- 
They have never been found attached to the trichogyne-like structure. 
They are, however, often found around the mouth of the perithecium, 
sometimes in clusters. 
1) FRANK, B., über Gnomonia erythrostoma , 
die Ursache einer jetzt 
herrschenden Blattkrankheit der Süßkirschen im Altenlande, nebst Be¬ 
merkungen über Infection bei blattbewohnenden Ascomyceten der Bäume überhaupt 
(Ber. D. Bot. Ges. 4, p. 200-205, 1886). 
2) Fisch, C., Beiträge zur Entwicklungsgeschichte einiger 
myceten (Bot. Ztg. 40, p. 851-870, 875-897, 899-906, pis. 10, 11, 1882). 
Asco- 
