NOTES ON THE ERYSIPHACEAE 207 
radformig-strahlig sich verbreitenden Mycelfaden sich aufbauenden 
besonderen Mycelium. Ascilanglich mit 1-5 Sporen. Anhangsel 
ahnlich denen von Ph. guttata. Conidien wurden bis jetzt noch 
nicht beobachtet. Auf verkiimmerten Fruchtkérper von Boletus 
bei Vinkovce in Slavonien K6nigreich Ungarn.” From this de- 
scription we may conclude, I think, that perithecia of P. corylea, 
attached by their penicillate cells to the pileus of the Boletus, were 
under observation. In Schulzer’s original diagnosis (Oest. Bot. 
Zeit. 26: 58. 1876), the description occurs, “Die Pyrenien 
[= perithecia] sitzen, jede fiir sich, auf einem aus strahlenformigen 
kiirzeren und langeren Hyphen bestehenden Mycelium,” The 
“mycelium” here described by both authors, probably refers as 
Neger (53) has suggested, to the spreading penicillate cells, which 
frequently form a membranous mycelium-like layer under the 
perithecium and often extend a little way beyond it. : 
The loosening of the perithecium from its original point of 
attachment is, as Neger (54) has pointed out, brought about by 
a special contrivance. The wall of the bulbiform base of the 
appendages is, according to Neger, thickened in all parts except 
in the lower quadrant nearest the perithecium (see f/. 77, f. 20, 
21), copied from Neger. If a living perithecium (the appendages 
of which will be spreading horizontally more or less in the plane 
of the leaf on which the fungus is growing) is placed in a dry 
atmosphere or in a salt solution, the watery contents of the basal 
bulbous part of the appendage diffuse through the thin-walled 
Part. This causes a folding to take place at this spot (see /. 
20) and a consequent turning downward of the whole ap- 
pendage, until at last the perithecium is forced away from its 
Point of attachment and stands loose on the points of the reflexed 
appendages, In a damp atmosphere, or in contact with water, 
the bulb swells out again in the folded part, and so causes the 
‘ppendages to become horizontal again. Neger observes that an 
@ppreciable force is exerted by the appendages in turning down- 
wards in the manner described above, and mentions that a rather 
thick cover-glass, which was placed on four perithecia, was, in an 
exsiccator, easily raised up by them. 
| It is worth while noting that some examples of P. cory/ea on 
Fraxinus excelstor possess asci which nearly always contain three 
