36 TEXT-BOOK OF FUNGI 



Excepting the Perisporieae the vegetative portion of 

 the fungus is immersed in the substratum on which the 

 plant is growing, and the portion growing in the air is 

 entirely devoted either directly or indirectly to reproduc- 

 tion, and is called the sporophore. Thus in the common 

 mushroom (Agaricus campestris), the stem, cap, and gills 

 bearing the spores collectively constitute the sporophore, 

 whereas the mycelium or spawn hidden away in the ground 

 represents the nutritive portion of the fungus. As an 

 exception to the above general statement, it may be pointed 

 out that in some of the primitive types of fungi belonging 

 to the Phycomycetes, as species of Saprolegnia, etc., the 

 vegetative and reproductive portions are not sharply 

 differentiated, and both are immersed in the substratum, 

 which on decay liberates the spores. Such species are 

 aquatic in habit, and spore distribution is effected by 

 water, but when fungi became terrestrial in habit and 

 dependent on wind for spore dispersion, then the sporo- 

 phore became superficial ; in those instances where the 

 fruit is immersed in the matrix, as in species of Sphaeria, 

 Valsa, etc., some provision is made, either in the form of 

 a tubular neck to the fruit, reaching above the surface of 

 the matrix, or the rupture of the latter, for liberating the 

 spores in the air at maturity. 



As would be expected in such an enormous assemblage 

 of species, the variety of form and relative complexity of 

 structure of the sporophore is manifold. In some primi- 

 tive forms as the Chytridiaceae, where the mycelium is 

 almost obsolete, the conception of a sporophore is not 

 possible, and the same may be said of the oospores of 

 the Peronosporeae, etc., that are borne on short lateral 

 branches, or intercalary^-that is, produced from certain 



