516 The American Naturalist. [June, 
the fungus; that the fungus is strictly connected with that 
part of the plant which absorbs the food materials; and that 
those orchids which are chlorophyll-less, and therefore depend 
on the humus of the soil for carbonaceous matter, always 
exhibit this fungus highly developed. Accordingly, he includes 
this too in Mycorhiza, calling it “ endotropic Mycorhiza” (i. e. 
the hyphe live in the cells) as opposed to “ ectotropic Myco- 
rhiza ” in which the fungus is entirely outside of the cells. 
As to Frank’s statement that the’ protoplasm of the cell is 
not affected by endotropic Mycorhiza, Marshall Ward, in the 
Annals of Botany for February, 1888, says: “ This can only be 
an assumption, and the impression I gather from the study of 
what is known of this orchid fungus is in favor of the view 
that the fungus does disturb or ‘ parasitically affect’ the proto- 
plasm of the cell, and that an outward and visible sign of some 
such action exists in the hypertrophy of the cells affected and 
in the turning yellow of the chlorophyll-grains.” 
R. Hartig, a more sober and trustworthy writer than Frank, 
said the last word so far on Mycorhiza in 1891. He admits 
that the mycelia of some of the Tuberacex or Gasteromycetes are 
found symbiotic with the roots of certain trees. But his con- 
clusion is that they are of no use to the tree, and are probably 
injurious by taking nourishment properly belonging to the 
tree. It would seem that they must do this, even were there 
mutualism between them and the roots—else why are they 
there? Organisms are not given to gratuitously assisting one 
another. © Mycorhiza undoubtedly exists—i. e., mycelial stages 
of many fungi of different groups are parasitic upon and in 
the roots of anthophytes. But that there is, in any of these 
cases, more than the ordinary symbiosis of parasite and host, 
has not been shown, and is improbable. That every tree has — a 
its root system covered with mycelia, proves nothing. Every 
tree has its bark covered with lichens, its twigs with black 4 
fungi, and its leaves with parasitic fungi of every description. = 
The second case of “ Wurzelsymbiosis” is the root tubercles 
of the Leguminose. These tubercles have long been known 
upon clover, and of late years—since 1885, in fact—have been — 
found upon nearly all of the Leguminosæ. Naegeli found & 
