Chapter 8 

 SPORE DISSEMINATION 



All students of fungi are impressed with the seemingly limitless 

 profligacy of these organisms in the production of spores. Arthur 

 (1929) records that more than 2 billion sporidia may be formed 

 by a single gall of Gymnosporangimn juniperi-virginianae. 

 Fovies applanatiis, which may attain a size of 0.75 X 0.5 meters, 

 may have an annual production of 5 million million spores. The 

 crop of aeciospores from a single barberry bush was found by 

 careful computation to be 64,512,000,000. The pileus of Psalliota 

 ccnnpestris may produce 1,800,000,000 basidiospores, that of 

 Coprimts comatus 5 billion, and that of Poly poms squamosus 1 1 

 billion. 



Meyer (1936) reported that a sporophore of Tomes fomentarius 

 shed 1115 grams of spores in a period of 20 days. Each spore had 

 a computed weight of 0.000,000,000,146 gram. The calculated 

 number of spores produced by this sporophore, therefore, was 

 7,636,986,301,369. 



Moss ( 1940) estimated the number of spores formed by Calvatia 

 gigantea as 20 million million. This ability to produce spores in 

 abundance is made possible among many Basidiomycetes by the 

 lar^e size of the fructifications and by such structural modifica- 

 tions as gills and pores that increase the spore-bearing surface. 

 Certain leathery and woody polypores have been found to be 

 capable of shedding spores continuously for 6 months or longer. 

 Organisms in other groups may shed spores in abundance only 

 under special conditions. Monilia sitophila, for example, may 

 cover burned sugar-cane stubbles to the extent that acres of land- 

 scape look pink. The metal lic-lustered Blakeslca trispora may be 

 equally widely prevalent on mowed, withered Sida spinosa and 

 other weeds in orange groves. Heald (1937) states that Tilletia 

 tritici may be so abundant during the threshing season in eastern 



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