240 



smiiU pièce of the bark, from the junction of sound and 

 diseased tissue, with a knife, which had been passed 

 through a flame, and placing this pièce of bark on a ste- 

 rilized nutrient médium. This médium was generally a 

 décoction of cacoa fruits vvitli 2% agar-agar. The fungus 

 developed rapidly and soon covered the médium with a 

 grey, woolly mycélium, on which after a short time the 

 fructifications were formed. They are depicted in Figs 5 and 6. 

 Thèse pycnidia do not hâve the regular bottle shape of 

 the fructifications formed on cacoapods or branches which • 

 will be described below. They are often curved ; sometimes 

 the cavity, in which the spores arc formed, is also strongly 

 curled, so that it is eut several times in transverse sec- 

 tion (Fig. 6). The pycnidia bear hairs; the spores are at 

 first colourless and unicellular, but afterwards dark and 

 bicellular in conséquence of the formation of a septum 

 (Fig. 7). Thf structure of apycnidium is seen more clearly 

 in fig. 8 wliich was drawn from a préparation out of 

 a cacoa fruit. The wall of the fructification in Fig. 8 con- 

 sists of a pseudo-parenchymatous tissue; its outer layers 

 are black, tlie inner ones colourless. In the drawing only 

 a few spores hâve been indicated, but in reality they are 

 formed in this colourless portion in large numbers on 

 sterigmata, between which long threads, the paraphyses 

 Project into the cavity. The latter is often completely 

 filled with spores, which at that stage are still unicellu- 

 lai' and colourless; it is iiot until they hâve passed out, 

 tliat they become bicellular and acquire a darker colour 

 (Fig. 7). Kipe spores are 22—28 microns long and 11 — 14 

 microns broad. The neck of the pycnidium projectsoutside 

 the pericarp and is covered with hairs. The round opening, 

 through which the spores pass out, cannot be seen in 

 Fig. 8 because the section passes obliquely through the 

 fructification. 



