THE FUNCTIONS OF THE STIPE 41 



are so constructed that in ordinary weather they remain quite 

 motionless. Those with the longest stipes, e.g. Coprinus comatus, 

 scarcely sway on very windy days, whilst most fruit-bodies remain 

 practically unstirred even during gales. In a field, the stability of a 

 Mushroom may be contrasted with the instability of a neighbouring 

 grass stem ; but we must recognise that the peculiar mechanical 

 properties of both Cryptogam and Phanerogam are equally fraught 

 with a beautiful significance. Each plant reacts to the motion of 

 the breeze in a manner most suited to its own special needs. 



Centric stipes are usually cylindrical. In some species, e.g. 

 Russulse, &c., the cylinder is quite solid, although, as a rule, it is 

 firmest toward the exterior ; in others, it has a narrow central core, 

 stuffed with soft, loosely interlacing hyph«, or left quite unfilled as 

 in Amanita phalloides (Fig. 13) or the Mushroom; whilst in yet 

 others, of which Coprinus comatus is a good example, it assumes 

 the form of a perfect hollow cylinder with a comparatively thin wall 

 (Plate I., Fig. 1). The hollow cylinder has the same significance in 

 Fungi, in Flowering Plants, and in structures built by engineers. 

 Where it is employed, advantage is taken of the fact that with a 

 given length and a given amount of material, a hollow cylinder is 

 more rigid and offers more resistance to bending than a solid 

 one. 



Where the pileus is large, as in many Russule and Boleti, the 

 stipe is usually thick, solid, and so rigid or tough that it is not easily 

 displaced ; it appears to be constructed as if to resist more particu- 

 larly any downward pressure from above, arising from obstacles met 

 with in pushing up the broad pileus, or which might come to rest 

 on the fruit-body after its development. On the other hand, there 

 are many species with small pilei placed on long stipes. Here the 

 pileus is usually conical or dome-shaped, and the stipe forms a 

 perfectly holloAv cylinder or one with a thin firm wall and a very 

 soft core. The whole fruit-body, whilst being fairly rigid, is much 

 more elastic than the larger ones to which we have referred, and 

 seems adapted for pushing its way up between surrounding grass 

 stems, &c., for throwing off rain-water, and for resisting lateral 

 pressure. Illustrations of long, hollow stipes may be found in the 

 genera : Mycena, Galera, Stropharia, Coprinus, &c. Thin-stiped fruit- 



