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carbo-hydrates, is, after all, nothing but a parasite on the micro- 

 scopic fungus hidden in the ground below. That this is an ex- 

 treme view may easily be recognized when the real facts, which 

 are known to be facts, are taken into consideration. That the 

 plant has no other means of getting nourishment from the ground 

 than through these hypha^ is a known fact. But on the contrary, 

 nothing is known of the true nature of this food when given over 

 to the plant If it were proven that the fungus takes up elabor- 

 ated food from the humus in which it is found, and passes that 

 food over to the tree, it could not then be considered the host 

 from which the tree gets its living, but only the conductor of 

 food. It is conceded by even the most conservative that the 

 tree may obtain some elaborated or energized food in this way; 

 but the real idea of parasitism includes a greater dependence 

 of the parasite upon its host, or rather a different kind of depen- 

 dence than this, namely^ a plant liviqg upon another, by taking 

 the food which is elaborated by this plant for its own purposes. 



Now, in the Mycorhiza it is not known even that the tree re- 

 ceives food drawn from the humus through the hyphiE. That 

 this is presumably the case adds nothing to substantiate Prof 

 Frank's statement that the beech tree is a parasite. 



In regard to the point about the lack of the root hair, the 

 statement made is correct so far as actual experiments have 

 been tried. Yet it would not be at all surprising if an experiment 

 should show that the plant had lost its power of producing root 

 liairs. The general law of inheritance is, that a plant possessing an 

 organ whose function is usurped by that of some other organ, 

 extraneous or otherwise, in the course of generations loses its 

 power to develop this organ. There is no question but that 

 some very interesting biological facts are yet to be discovered in 

 this field. The relationship between plants of different groups, 

 which has been conveniently named Symbiosis, has been proven 

 to be of so varied a nature that the word itself has scarcely any 

 definite meaning. In the earlier history of this word, in its ap- 

 plication to botany, some botanists tried to limit its use to that 

 relationship by which two plants of different groups are geneti- 

 cally connected with each other, neither being injured by this 



