59 
hours in hanging-drops of sugar-cane extract, prune decoction, 
or distilled water. During germination they become septate, and 
extrude hyaline, septate, finely-granular germ-tubes of a thickness 
of 34. The germ-tubes may branch quite early. After twenty- 
four hours, numerous dark-brown appressoria are formed; in a 
further eighteen hours, the hanging-drop appears to the eye as 
a mass of white hyphae. In solid media, the fungus grows 
rapidly. Aerial white flocculent mycelium appears overnight, 
and conidial formation takes place in three or four days. On 
sterilised blocks of coffee-wood in Roux tubes results are similar, 
and subsequent examination shows the hyphae of the fungus to 
have penetrated the blocks. Setal formation takes place com- 
paratively seldom. It may depend on the amount of moisture 
present or on the age of the acervulus, but modifications in the 
- moisture content of the Roux tubes did not seem to influence 
the appearance or non-appearance of the setae. On the acervuli 
of Colletotrichum on twigs in a damp chamber, setae frequently 
do nct develop at all, or they may appear late when: conidial 
production is slackening down. They may be, for example, only 
half the length given by Zimmerman for the setae of Colletotrichum 
incarnatum* five days after the conidia are ready to, and do, 
germinate. On sterilised coffee leaves, the fungus produces no 
setae. This is the case also in nature when the fungus attacks 
the leaves. On the berries, again, setae may or may not occur. 
The presence or absence of setae is thus an inconstant character, 
and, though it has been usual to refer setae-less acervuli to the 
genus Gloeosporium, the writer’s opinion is that the acervuli and 
conidia of Gloeosporium on the leaves (G. coffeanum, Del.), and the 
Colletotrichum on the stems are indistinguishable and that the 
two species may well be the same. Cultures were prepared from 
stem, leaf, and berry material, 7.e., from both Colletotrichum and 
Gloeosporium spores, and no differences could be detected in the 
growth of the various mycelia or in conidial formation. It is 
generally agreed that the separating line between Colletotrichum 
and Gloeosporium is a narrow one, and that the basis of dis- 
tinction is artificial, and it would appear that the presence or 
absence of setae is governed more by physiological conditions 
than by a hard-and-fast morphological rule. 
Inoculations with Colletotrichum coffeanum.—Material con- 
sisting of conidia and mycelium from the cultures was used in 
inoculation experiments in the study of coffee dieback. Inocu- 
lations were made (1) by wounds and punctures on twigs at the 
nodes, in the course of the internodes, and at the tender growing 
point of the stem, and (2) by placing the inoculum on both 
surfaces of leaves, on the unwounded bark of nodes and inter- 
nodes of twigs, and upon the apical growing point. Young 
healthy plants were used for the most part, but fresh healthy 
twigs were also employed. The latter were kept in cylinders of 
* Noack gave no measurements of the setae of C. coffeanum. 
