Vol. 5, No. III.] JOURNAL OF MYCOLOGY. [September, 1889. 
CONTRIBUTIONS TO THE HISTORY OF THE DEVELOPMENT OF THE 
PYRENOMYCETES. 
(Plate XI.) 
By Franz yon Tavel. 
[ Continued from page 58.] 
III. Fenestella Platani, n. s. 
Several dry branches of Platanns attacked by Discula platani and 
two forms of Gytispora were placed in moist air and left to themselves. 
It was the end of October before the observations could be taken up 
again. The Gytispora forms were still present, and between them pro¬ 
truded a number of long black necks of the perithecia of a Pyrenomy- 
cete not described in any of the systematic works which we used. Jt 
was, therefore, very minutely examined; its development could not, of 
course, be followed out completely, but it yielded some noteworthy re¬ 
sults. 
The starting point of the investigation was, as has been said, a form 
of Cytispora. The great variability of this form makes itdoubtful whether 
or not it is identical with G.platani , described by Fuckel, E. F. N., No. 
334. While still in the younger stages Gytispora shows itself on a branch 
in the form of small swellings 1-3 millimeters in diameter. The bark soon 
ruptures and the well known worm-shaped masses, which here have a 
waxy-yellow and often a whitish color, project through the openings. 
Upon removing them a black body, the stroma, may be seen through 
the crack in the bark. The stroma continues to increase in size, mak- 
.ing the opening in the bark wider and then projecting through it. In 
the meantime new spore-masses protrude. The branches were kept in 
tall cylindrical jars containing some water at the base. It was apparent 
that the largest stromata existed at the base of the branches while the 
fungus developed very sparingly at the tips. It seems, therefore, that 
a high degree of moisture promotes the growth of the fungus. Fully- 
developed specimens of Gytispora often attain a diameter of one-half a 
centimeter; ten spore-masses may project from the stroma at the same 
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