XVIII GERMINATION OF SPORES 189 



of the sterigma as a globular daughter-cell, in very much the 

 same way as a bud is separated in Saccharomyces (p. 73). 

 In this way a spore is produced. The process is repeated : 

 the end of the sterigma is constricted again and a new spore 

 formed, the old one being pushed further onwards. By a 

 continual repetition of the same process a longitudinal row 

 of spores is formed (k'', f'"'), of which the proximal or lower 

 one is the youngest, the distal or upper one the oldest. The 

 spores grow for some time after their formation, and are 

 therefore found to become larger and larger in passing from 

 the proximal to the distal end of the chain (f*^). Sooner or 

 later they lose their connection with each other, become 

 detached, and fall, covering the whole growth with a fine 

 dust which readily adheres to all parts owing to the some- 

 what sticky character of the spores. In this stage it is by 

 no means easy to make out the structure of the brushes, 

 since they are quite obscured by the number of spores 

 adhering to them (f"). 



It is at the period of complete formation of the spores that 

 the growth turns green. The colour is not due to the pres- 

 ence of chlorophyll. Under a high power the spores appear 

 quite colourless, whereas a cell of the same size coloured 

 with chlorophyll would appear bright green. 



The germination of the spores can be readily studied by 

 sowing them in a drop of Pasteur's solution in a moist chamber 

 (Fig. 37, p. 163). The spores, several of which usually adhere 

 together, are at first clear and bright (b^) : soon they swell 

 considerably, and the protoplasm becomes granular and 

 vacuolated (b^) : in this stage they are hardly distinguishable 

 from yeast-cells (compare Fig. 12, p. 72). Then one or more 

 buds spring from each and elongate into hyphae (b, c), just 

 as in Mucor. But the difference between the two moulds is 

 soon apparent : by the time a hypha has grown to a length 



