122 TEXT-BOOK OF FUNGI 



continues to grow, somewhat slower than at ordinary tem- 

 peratures, and normal sporangia are formed. The author 

 considers that as respiration is entirely suspended at this 

 temperature, the theory that respiration is a necessary 

 condition of vegetable life requires modification. 



It is quite probable that spores will bear without injury 

 a temperature much lower than indicated above, as Sir 

 William Thiselton-Dyer has shown that the seeds of some 

 flowering plants, Brassica alba, Pisum sativum, Cucurbita 

 Pepo, Mimulus moschatus, Triticum sativum and Hordeum 

 vulgare, were not in any way impaired by exposure to a 

 temperature of 250 C. for over an hour. 



Chodat, Bull. Herb. Boiss., p. 890 (1896). 



Bot. Centralbl., 70, p. 242 (1897). 

 Thiselton-Dyer, Ann. Bot., 13, p. 559 (1899). 

 Eriksson, Kgl. Land. Akad. Handl. Tidskr., 34, p. 216 

 (1895). 



EFFECT OF MECHANICAL MOVEMENTS 

 ON GROWTH 



According to Russell, the form and size of fungus cells 

 are but little influenced under constant agitation ; hyphae, 

 however, are not formed freely. Such conditions greatly 

 favour the increase in the number of cells, and conse- 

 quently the amount of organic matter produced. The 

 chief reason is considered to be more perfect aeration and 

 the better conditions of nutrition. 



Russell, Bot. Gaz., 1892, p. 18. 



