202 



BOTANY OF THE LIVING PLANT 



Externally no fungus is obvious, but if sections of the root be cut the third 

 to the fifth layers of the cortex have their cells crowded by coiled fungal 

 hyphae, which are enclosed in the still living nucleated protoplast. The infec- 



Fic, 153. 

 Ncottia nidus-avis, .-i^young tuber in section sjiowing infected region sliaded. 

 i.' = rather older plant seen from outside. C — diagrammatic section of plant at 

 period of flowering, showing scale-leaves, axillary buds, and the insertion of the 

 prominent roots. The infected regions are shaded. D = rhizome seen from outside, 

 with roots removed: the scars (cs) show hoT\ numerous the roots are. [A, B, C 

 after Bernard ; D after Irmisch.) 



tion has been found to start with the germination of the seed, and is probably 

 not repeated (Fig. 154). Tufts of hairs, such as are present in Corallorkiza 

 and many other Orchids, are absent : but conimunication is kept up with the 

 soil by occasional hyphae which traverse the superficial cells. According to 



Seed of Xcviiui infected 



l:iy fungus, and showing the first sta^ 

 (After Bernard.) { - roo.) 



of genuination 



age and position the fungal filaments show various stages of disorganisation. 

 In some cells only the indigestible retunants of the hyphae remain. The nuclei 

 of the digesting cells meanwhile increase in size, and starch appears in quantity 



