380 BOTANICAL GAZETTE [JUNE 
of black sclerotial crust is formed, an inch or more in diameter, 
but not much thicker than paper. Fig. 2 and ‘ext fig. 1 d show 
the small sclerotia of this type, and the crust-like growth is 
shown by éext fig. z 6 and c¢, and by fig. 437. Aclear distinction 
can be seen between the formation of sclerotia in this and in the 
botrytis form. Here they first appear as white specks in the 
mycelium, gradually becoming black and hard. They are notas 
long as those of the other form, and lack entirely the very char- 
acteristic blister-like connection with the substratum, being 
entirely distinct from it and imbedded in the mycelium. They 
are also produced much more abundantly. Many trials were 
made to obtain further development from these sclerotia. When 
placed on moist sand they usually produced a growth of mycel- 
ium, more copious from old specimens than fresh ones. Old 
dry material a year old grows luxuriantly when kept moist for a 
few days, producing much more mycelium than the Botrytis 
sclerotia. What might be called secondary sclerotia are also 
produced on such growths. On the surface of clean sand, on 
moist filter paper, or even on the bare bottom of a glass dish, 
when kept covered and moist, the mycelium coming from a scle- 
rotium produces often a considerable number of smaller ones. 
The same result is often seen when a piece of affected tissue is 
placed in a moist chamber ( fig. 45); and upon the surface of the 
soil about, and especially beneath the leaves of the affected 
plants, such secondary sclerotia are commonly produced. Being 
so small, however, they are difficult to distinguish in the latter 
case. Other than this no development has been obtained from 
these sclerotia except in one case. One of the largest speci- 
mens, about 3™™ in diameter, after being in the sand for some 
time, threw up a slender stalk (jig. 35). This reached a height 
of nearly 1°, but then withered and faded away without attain- 
ing any farther development. 
Since no reproductive structures of this form could be 
obtained, infection experiments were only possible by using dis- 
eased tissue or masses of mycelium as infective material. Such 
experiments were almost invariably successful. Using plants 
