A XEROPHYTIC FUNGUS FLORA 109 



safe to state that very many, and possibly all, of the small leathery 

 and corky fruit-bodies of Hymenomycetes which are to be found 

 developing on fallen logs and sticks in woods, are capable of com- 

 plete recovery after desiccation. In a number of instances they can 

 be kept dry for months or even for several years, apparently without 

 the smallest detriment to their power of liberating spores after 

 absorbing water once more. Among the species in question one may 

 mention those belonging to the following genera : Schizophyllum, 

 Lenzites, Trogia, Dsdalea, Polyporus, Polystictus, Merulius, Phlebia, 

 Stereum, and Corticium. These fungi must be regarded as xero- 

 phytes, for their fruit-bodies are capable of withstanding drought 

 by drying up without any loss of vitality and of reviving again 

 under moist conditions. 



Fruit-bodies of Lenzites, Polystictus, S:g., which were required 

 for testing:, were sfathered durinsf October and November from 

 stumps, logs, and sticks in the woods near Winnipeg, and placed 

 on a table in the laboratory. There the air was very dry, so that 

 desiccation took place rapidly. A dried fruit-body, still living, 

 revived when it had been set in a damp-chamber and wet cotton- 

 wool had been placed on the top of its pileus. It quickly absorbed 

 the free water, expanded, and soon came to have a fresh appear- 

 ance. After a few hours spore-liberation was resumed. This was 

 proved in my first experiments by collecting spore-deposits on paper, 

 but subsequently this method was discarded and the beam-of-light 

 method used instead. It has already ^ been made sufficiently clear 

 that a strong beam of light, directed beneath a fruit-body in a closed 

 beaker, readily enables one to determine whether or not spore-fall 

 is taking place. 



As a rule, only a very few hours are required for a dried-up 

 fruit-body to regain its spore-liberating function. A specimen of 

 SchizopJii/llum commune, kept dry for six months, recovered in 

 three hours. Merulius corium and Polystictus versicolor, kept dry 

 for six months, and Lenzites betulina, kept dry for two years and 

 six months, all required about four hours to recover. In other cases 

 it was found that spore-fall usually recommenced within six hours 

 after the fruit-bodies had been placed under moist conditions. A 



1 Chap. VIIT. 



