1896.] MICROSCOPICAL JOURNAL. 83 



4.) To this mass of hyphas the name of mycorhiza was 

 given, and it was looked upon first as a parasite and then 

 as a symbiotic fungus. Let us now look carefully at the 

 conditions of growth and we shall then see that we are 

 dealing with a case very different from that of the 

 lichens. We have, it is true, a fungus associated with a 

 green plant, but here a large green flowering plant, 

 which would not let itself be entirely overcome by a 

 small fungus. The fungus too lives under different con- 

 ditions. It is not growing on arid rocks or trees, but 

 usually in decaying vegetable matter, the fallen loaves of 

 the tree, which would enable it, as it is of a saprophitic 

 nature, to live independently. The flowering plants, on 

 the other hand, cannot, as a rule, make use of decaying 

 vegetable matter. They feed on organic salts, which they 

 take up, dissolved in water, by their thin root hairs. 



In the cases however in which the roots are infested 

 with a mycorhiza, they are so completely covered in, 

 even up to the tip, that they develop no root hairs at 

 all. How then can they absorb nutriment ? Well, as a 

 matter of fact, they may be said to be fed by the my- 

 corhiza. On the outside of the felting formed by the 

 fungus, numbers of hyphse can be seen making their way 

 in all directions among the decaying leaf-mould, and 

 fixing themselves just like the root hairs of the tree would 

 do to particles of the soil. On the inside, where the 

 mycorhiza touches the root, the hyphae will be seen mak- 

 ing their way between the epidermal cells, which should 

 have grown out into root hairs. (Fig. 5.) These epider- 

 mal cells no doubt absorb food matter from the fungus 

 which the latter, saprophyte that it is, has been able to 

 obtain from the decaying mass of leaves. That this is the 

 case, and that the trees really derive much nourishment 

 from the mycorhiza, has been proved by experiments such 

 as germinating beeches in pure leaf-mould, when the 



