THE FUNCTIONS OF THE STIPE 



43 



in different species, so that its peculiar mechanical needs are 

 doubtless met in slightly different ways. 



In certain species of Polyporus which have central stipes — 

 P. pisochapani, P. rugosus, P. lepideus, and P. floccopus — there 

 is present, according to Massee,^ a highly developed mechanical 

 sheath to both pileus and stipe. The occurrence of this structure 

 points to an unusually marked division of labour between the 

 nutritive and supporting parts of the fruit-bodies. 



In Goprinus comatus (Plate I., Fig. 1) the pileus has the form of 

 a bell, and its centre 



C 



of gravity is situated 

 at some distance be- 

 low its place of at- 

 tachment to the stipe. 

 It is thus in a state 

 of stable equilibrium, 

 and doubtless, in cor- 

 relation with this 

 mechanical fact, it 

 happens that the pi- 

 leus and stipe are very 

 loosely attached to- 

 gether. If one slightly 

 tilts the stipe of a 

 fruit-body which has 

 just opened, the pi- 

 leus refuses to become 

 tilted too, but instead remains in its optimum position. High 

 winds sometimes cause the pileus to swing slightly about the fixed 

 stipe. However, few or possibly none of the spores would thereby 

 be prevented from escaping from the fruit-body, owing to the 

 peculiar manner in which they are liberated.- 



Among the most beautiful Agarics in nature are the so-called 

 Parasol or Umbrella Fungi — Lepiota procera and L. racliodes — 



Fig. 13. — Amanita phalloides [volwa, revnoved). A, young 

 fruil-body. B, mature fruit-body. The stipe has 

 been quadrisected and the tensions in it have caused 

 the four parts to separate. C, cross-section of a stipe. 

 All f natural size. 



^ G. Massee, " On the Ditlerentiation of Tissues in Fungi," Jonrn. Roy. Micr. 

 Soc, 1887, p. 205. 



* Vide infra, Chap. XIX. 



