l66 SAPROPHYTIC FUNGI 



There is also a complicated method of conjugation 

 which is comparatively rarely met with and will not 

 be described here. 



Other Saprophytic Fungi. There are numerous other 

 forms of saprophytic fungi, including many with com- 

 plicated reproductive bodies (" fruit bodies "), of which 

 the common mushroom (Agaricus campestris) is a 

 good example. The mycelium lives in the humus of 

 the soil, particularly in well manured pastures, and 

 resembles that of Mucor in a very general way, except 

 that it is septate, as are all the higher fungi. The 

 mushroom itself is the fruit body, which arises first as 

 a small weft of hyphae forming a portion of the fila- 

 mentous mycelium. This increases in size by constant 

 branching and grows into a small very compact nodule, 

 which increases in size and complexity, becoming 

 differentiated into a short stalk and an arched top. 

 Finally it grows up above the soil by the rapid elonga- 

 tion of the hyphse forming the stalk and expands the 

 umbrella-shaped pileus * or top of the mushroom. From 

 the tips of the hyphae which run at right angles to 

 the surfaces of the platelike " gills " on the underside 

 of the pileus there are budded off spores, four or two 

 from each hypha tip, each formed on a small projecting 

 point. The enormous number of spores produced by a 

 single mushroom may be gauged by placing a ripe 

 pileus, detached from its stalk, underside downwards 

 on a piece of white paper and leaving it for a day or 

 two. On gently removing the pileus a pattern of the 

 gills will be found designed in streaks of microscopic 

 spores on the paper. 



1 " A woven hat." 



