117 
be attached, it would nevertheless, under the present system of classifi¬ 
cation, be impossible to do otherwise without revising the character¬ 
istics of an entire genus and rendering its position in Saccardo’s artificial 
system impossible. These questions are for systematists to decide ; in 
the present investigation it is perfectly immaterial whether its object 
is called Fenestella or Pseudovalsa. 
As to the species, the one under consideration varies in the structure 
of its spores from all known species; that is, from all Fenestella and 
Pseudovalsa species cited in Saccardo’s “ Sylloge Fuugorum.” It can 
therefore be given the name of Fenestella platani. 
The ascospores retain the power of germination for a long time. Ma¬ 
terial that had been kept dry for five months yielded the same results 
as that which was fresh. This question now suggests itself: Into what 
do the ascospores develop? The resulting body differs with the sub¬ 
stratum. Cultures in nutritive solutions gave different results than 
those on fresh Platanus leaves. We will first follow the development 
of the fungus in a nutritive solution. 
In water, in a nutritive solution like a decoction of the plum, grape 
juice, or extract of meat, or in some such solution thickened with gelatine, 
the ascospore germinates, as a rule,within twenty-four hours. Germ 
tubes arise sometimes from all, sometimes from only one cell in the 
spore. They penetrate the strong spore membrane, and the protoplasm 
passes from the spore into the germ-tube, giving the former a paler appear¬ 
ance. Generally the germ-tube swells up immediately after its exit from 
the spore; this is especially the case in water cultures where the fungus 
does not develop any further. In this case the germ-tubes generally 
remain quite short, sometimes becoming almost globose and beginning 
to cut off spores. Under favorable conditions they grow somewhat 
longer and even branch, but become divided up into short roundish 
cells and form gonidia at the apex (Fig. 8). These are oval, unicellular, 
and colorless. They soon put out a germ-tube, sometimes two, which 
again detach gonidia in a short time. Their further development was 
not observed. 
In sowings upon gelatine which was mixed with a nutritive solution, 
the germ-tubes, unlike those sown in water, show a vigorous terminal 
growth, while their diameter increases very little; but even in this case 
the base remains thick and composed of short cells. The septa are 
formed at some distance behind the growing point, and numerous mon- 
opodial branches are also developed. On account of the large number 
of germ-tubes produced by the spore at the same time, and their vig¬ 
orous growth, the mycelium attains a very considerable growth in a few 
days, in the center of which the dark-colored spore remains visible for 
some time. 
After from five to six days some of the liyphae which have come to 
the surface of the gelatine, or those that run just underneath it, send up 
numerous branches composed of one or two cells and bearing a pretty 
