FUNGL. 271 



them these resting spores, which are set free and 

 recover activity in the spring. At this period the 

 resting spores are broken up into a number of small 

 active zoospores, which float in a film of moisture 

 until a favourable opportunity, when they settle 

 down to germinate and commence a new cycle. 



In a similar manner the true Mucors and the 

 SaprolegniacecB pass through a period of hibernation, 

 in which thick-coated zygospores perform the func- 

 tion of resting spores. 



The very large section of fungi known as the 

 Pyrenomycetes have their reproductive organs enclosed 

 within hard or tough capsules, or perithecia, which 

 are produced for the most part in the autumn upon 

 dead leaves, stems, or branches ; and during the 

 winter these remain on the damp ground, maturing 

 their fruit, which is in full perfection in the early 

 spring. In these cases the entire fungus passes 

 through the winter, not in a condition of absolute 

 rest, but of reproductive development. The maple 

 leaves, disfigured with large pitchy black patches in 

 the autumn, must lie on the damp ground through 

 the winter in order to perfect their ascigerous fruit, 

 and then known as RJiytisma acerinwn ; but the 

 same patches in the autumn contain within them 

 certain minute stylospores, not enclosed in asci, and 

 in this condition it has been described as Melasmia 

 acerina. The fungus with stylosporous fruit is essen- 

 tially the same fungus as that which later on has 

 sporidia enclosed in asci. The autumnal stage, or 

 Melasmia, was an imperfect condition ; the spring 

 stage, or Rhytisvia, is the perfect form, which has 



