264 BOTANICAL GAZETTE [APRIL 
whether the forms are restricted to their individual hosts, or can be 
successfully transferred from one host to another. The work already 
done by Hatstep,?*? SourHworTH,’? and others in transferring 
various forms occurring upon different fruits from one host to another 
by inserting the conidia in the tissue of the host, or by applying them 
to the surface of mature fruits does not seem to us to be conclusive. 
A mature fruit, especially when the surface is ruptured, might be 
regarded simply as a culture medium, and the fact that these organ- 
isms will grow upon it does not prove that they would grow upon the 
plant as a parasite. The only conclusive test of this matter must be 
made by careful infection experiments, using fresh, living, and growing 
plants controlled by checks. SHELDON’ reports having done this 
in the case of the anthracnose of the apple, having succeeded in 
infecting the leaves of the sweet-pea by transferring conidia from the 
apple. These experiments, in connection with others which have 
been reported to us verbally, seem to indicate that some of these forms 
are not physiologically distinct. In some cases at least the evidence 
indicates that plants which appear free from disease are already 
infected, the fungus apparently being in a dormant or more or less 
inactive condition and awaiting favorable conditions for develop- 
ment. In the anthracnose of cotton and bean, the disease is known 
to be transmitted by diseased seed. It is desirable, therefore, that 
plants used for infection experiments should be grown from healthy 
disinfected seed under such conditions as to prevent the possibility 
of infection from other sources. In the present state of our knowl- 
edge, perhaps it may be best to regard the various forms we have 
studied as varieties of one species. 
The bodies frequently found in nature and in cultures, which have 
been called by some chlamydospores and by others appressoria, 
show no specific characters. While their function, perhaps, may be 
primarily that of appressoria or hold-fast organs, as maintained by 
PER and others, they are often produced under conditions 
ED, B. D., Laboratory study of fruit decays. Report N. J. Agr. Exp- 
Sta. sian or 1893. é 
12 SOUTHWORTH, E. a Ripe rot of grapes and apples. Jour. Myc. 6:164. 1891- 
3 SHELDON, J. L., Concerning the identity of the fungi causing an anthracnose 
of the sweet-pea and the bitter-rot of the apple. Science N. S. 22:51. 1905- 
«4 HASSELBRING, H., Appressoria of the anthracnoses. Bot. GAZETTE 42:135- 1906. 
