^76 



LIFE-HISTORY OF PHOMA CITRICAHPA. 



of Cytosporella vitiada. Only failure lias thus far met the 

 various attempts to germinate these bodies." 



Gehmination of the Spores. 



The normal pycnospores do not germinate readily in water. 

 After several days, a few may send out an attenuated hypha, 

 which seldom develops branches, and soon ceases to grow. 



In a nutrient solution (containing amm<niium nitrate, 10 gram; 

 dihydrogen potassium phosphate, Go gram; magnesium sulphate, 

 0*25 gram; iron chloride, trace; cane sugar, 5'0 grams; water, 

 100 c c.) the spores assumed a dark olive green colour, and only 

 a few commenced to germinate after several days. The hyphse 

 produced were a very dark green colour; they appeared stunted 

 and unable to elongate (PI. Ixxxvi., fig.lO). When a solution of 

 equal parts of peptone-water and this solution was tried, ger- 

 mination was somewhat better, but unsatisfactory. In an 

 aqueous extract of orange-peel, however, the spores germinated 

 freely. The rapidity with which the spores germinated in this 

 medium appeared to depend largely on the age of the spore If 

 placed in the solution immediately they were discharged from 

 the pycnidium, the spores had produced a germ-tube in twelve 

 hours. If, however, the spores were three days old, they took 

 several days to germinate; and, if much older, many of them 

 failed to germinate at all. The germinating spore usually sends 

 out a germ-tube from the side, but it may produce a germ-tube 

 from one end, or from both ends simultaneously. The granules 

 in the spore assume a greenish hue, and pass, for the most part, 

 into the germ-tube. A septum may be produced in the germ- 

 tube early, or the production of septa may be deferred (PI. Ixxxvi., 

 tig. 11). The hyphai soon branch, their ends being at first lound, 

 and, innnediately behind the tips, the cell-contents are usually 

 highly granular (PI. Ixxxvi., fig. 12). 



By taking special pre(;autions to prevent the hanging drop 

 from drying up, and to have every part of the apparatus and 

 instruments used sterile, T have been able to follow the develop- 

 ment of a spoi-e in a hanging drop from the production of a germ- 

 tube to the formation of a pycnidium by the mycelium, and the 



