BOTRYTIS CINEREA. 183 



its dry weight. Amongst organic acids, oxalic acid is widely 

 distributed. 



A whole series of colouring matters are found in the cells 

 of these plants. The colouring matter present in so many of 

 the bacteria is specially interesting, and has been shown to 

 play an important part in their vital economy. The fatty 

 colouring matters or dye-stuffs combined with fatty acids 

 (lipochromes) are of frequent occurrence. Allusion may also 

 be made to tannins (found in alcohol-producing yeast), resins, 

 and ethereal oils. 



1. Botrytis cinerea (Sclerotinia Fuckeliana) (Fig. 32). 



Botrytis cinerea forms small greyish-yellow patches on 

 moist decaying vegetable matter, and may also occur on 

 wort. From the greyish-brown mycelium the conidophores 

 are thrown up ; these are perpendicular articulated fila- 

 ments, generally arranged in tufts. They grow up to a 

 height of 1 mm., after which the apical cell throws out 

 near its point, and almost at right angles, from two to six 

 small branches (C"). The lower branches are the longest ; 

 these again give rise, at a short distance behind their 

 apices, to one or more short side branches. The topmost 

 branches are almost as wide as they are long. Thus a system 

 of branches is formed shaped like a cluster of blossom or 

 bunch of grapes. When longitudinal growth is at an end, the 

 interior of the branches is separated from the main stem by 

 the formation of a transverse wall close to the latter. At 

 the same time the ends of the branches and of the main stem 

 swell, and on the upper half of each swelling several small 

 papillae appear close together ; these quickly increase to oval 

 blisters, filled with protoplasm, and grow narrow and stalk- 

 like at their base. When these conidia (C') are completely 

 developed, the walls of the branches carrying them shrivel up, 

 and the conidia are consequently brought so closely together 

 that they form a loose, irregular aggregation, which readily 

 falls off. If these clusters are placed in water, the conidia 

 detach themselves from their stalks, and the envelopes of the 

 branches, devoid of protoplasm, shrivel up or are only to be 



