FORM AND CHARACTERS OF THE MUSHROOM. 



Parts Present in Other Mushrooms The Volva Some other mush- 

 rooms, like the deadly Amanita (Amanita phalloides) and other species 

 of the genus Amanita, have, in addition to the cap, gills., stem, and 

 ring, a more or less well formed cup-like structure attached to the 

 lower end of the stem, and from which the stem appears to spring. 

 (Figs. 55, 72, etc.) This is the volva, sometimes popularly called 

 the " death cup," or "poison cup." This structure is a very 

 important one to observe, though its presence by no means indicates 

 in all cases that the plant is poisonous. It will be described more in 

 detail in treating of 

 the genus Amanita, 

 where the illustra- 

 tions should also be 

 consulted. 



Presence or Absence 

 of Ring or Volva. 

 Of the mushrooms 

 which have stems 

 there are four types 

 with respect to the 

 presence or absence 

 of the ring and 

 volva. In the first 

 type both the ring 

 and volva are ab- 

 sent, as in the 

 common fairy ring 

 mushroom, Maras- 

 mius oreades; in 

 the genus Lactarius, 

 Russula, Tricholo- 

 ma, Clitocybe, and 

 others. In the second type the ring is present while the volva is 

 absent, as in the common mushroom, Agaricus campestris, and its 

 close allies ; in the genus Lepiota, Armillaria, and others. In the 

 third type the volva is present, but the ring is absent, as in the 

 genus Volvaria, or Amanitopsis. In the fourth type both the ring 

 and volva are present, as in the genus Amanita. 



The Stem is Absent in Some Mushrooms. There are also quite a 

 large number of mushrooms which lack a stem. These usually 

 grow on stumps, logs, or tree trunks, etc., and one side of the cap 

 is attached directly to the wood on which the fungus is growing. 



Figure 2. Agaricus campestris. "Buttons" just appearing 

 through the sod. Some spawn at the left lower comer. Soil 

 removed from the front. (Natural size.) 



