MICHIGAN ACADEMY OF SCIENCE. 
213 
cury. Then certain of these were placed in a damp chamber, where a 
Fusariwni, having the specific characters of those from the experimental 
plat, was developed within a couple of days, and isolated in a pure cul- 
ture. No other fungi appeared. Transverse sections of affected stems 
were now taken and submitted to microscopic examination, which showed 
a compact network of liyphae filling many of the vessels of the vascular 
bundles. It remains to demonstrate this cause of the disease, by making 
proper inoculations of healthy plants with suitable controls. I hope to 
take up this further work sometime in the near future. 
The next most abundant fungus was a species of Mucor, indicated as, 
— Mucor (species ?) . It has characteristic sporangia, but it is remark- 
able and somewhat difficult to identify, on account of the Avide varia- 
bility of its sporangiophores. In some situations, these form sympodi- 
ally in very characteristic manner, while in other cases, racemose clus- 
ters of the monopodial kind are predominant. It was certainly demon- 
strated that there was frequently a transition from the one type to the 
other. This came about by the elongation of certain racemose side 
branches, which as they elongated, began to branch sympodially. The 
spores Avere decidedly oval. This Avitli the sympodial character of the 
sporangiophore, seems to identify the species as “ ambigiius ” HoAvever, 
the racemose, monopodial development would, of course, throw it into an 
entirely different group. This wide variability might suggest the need 
of a neAv basis of classification for the Avhole group, or possibly, that 
this is a transitional form which shows extreme variations, allying it 
with both groups. 
SUMMARY. 
This investigation thus far, seems to justify the following generaliza- 
tion of results : 
1. An abundant fungous flora exists habitually in the soil, and the 
forms Avliieh make up this flora, carry out at least a part of their work 
and respective life histories in this habitat. 
2. This flora is to a conspicuous degree, constant in different soils, 
and also, rather uniformly distributed at all depths, at least as Ioav as 
14 centimeters. The species found belong mostly to the Hyphomycetes, 
or Imperfects; but include also a feAv of the Mucoraceae, among the 
Thy corny cetes. 
3. Tillage and manuring, so far as observations have been extended, 
seem to produce little change in the number and kind of species present. 
This statement is based on a study of samples taken from a manured 
plat, three months after the manure Avas applied, so that the fertilizer 
had become Avell decayed and mixed with the soil. 
4. Many of these fungi sIioav striking variability in their structural 
characters, Avhen cultivated on media of constant composition. 
5. One form Avhich sIioavs the structural characters of both Fusariinn 
and C epha losporiu in , is the probable cause of a destructive Avilt disease 
Avliieh attacks several species of garden flowers, including Aster , Siceet- 
pea. Zinnia , and Salvia s pie n dens. 
