INJURIES INDUCED BY PLANTS 



127 



hair-like filaments which stand more or less at right angles to 

 the mycelial strands (Figs. 68 and 69). 



These short simple or compound hairs produce a large drop 

 of ethereal oil at the apex, which finally rup- 

 tures the elastic cell-wall at the end of the hair, 

 and flows out. The hair thus comes to have 

 a funnel-like aperture at its apex (Fig. 69, e). 



I am not aware of attention having pre- 

 viously been called to the formation of 

 ethereal oil in the form of drops by fungi. 

 The oil is immediately dissolved by alcohol. 

 As the mycelial filaments in the periphery 

 of the strands contain numerous small oil- 

 drops, it would appear that this ethereal oil 

 is also exuded from the lateral walls of the 

 hyphae, although it is quite possible that this 

 has gradually found its way thither from the 

 apex of the hairs. When the filamentous 

 mycelia that envelop the soil-particles are 

 examined, it will be found that most of the thin threads possess 

 numerous clamp cells, and are somewhat brown in colour. 



FIG. 67. Mycelial 

 strands of Rhizina 

 which have been 

 cultivated in moist 

 air. They are part- 

 ly separated from 

 the wood. 



FIG. 68. A mycelial strand 

 bearing hairs. 



FIG. 69. a, a mycelial filament with an oil- 

 drop attached ; b, ditto, with an oil-drop at 

 the apex ; c, a hair with a large oil-drop ; 

 d, a bifurcated hair from whose apices the 

 oil-drops have become detached ; e, apex 

 of a hair viewed from above. 



Although I have much diffidence in maintaining that this 

 feature, which otherwise is peculiar to the Hymenomycetes, is 



