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6. At the point of infection a tubercle develops. This consists. 
of parenchymatous tissue rich in protoplasm in which the spores 
develop and multiply very rapidly. 
7. The mycoplasm becomes differentiated into nitrogenous 
(albuminous) ‘“‘Formelemente”—the “ Bakteroiden.” These re- 
semble bacteria. 
8, At the close of vegetation these stored bacteria-like col- 
lections of albuminous substances are again absorbed and utilized 
by the plant. 
9. Some tubercle-producing fungi of the Leguminose are 
purely parasitic; that of Phaseolus vulgaris probably belongs to 
this group. 
10. In most Leguminose the R/izobia have the power of ap- 
propriating for the use of the plant free nitrogen of the air. 
11. There is probably only one species of the Rhizobium 
which is present in all normal soils. 
12. Leguminose in rich soil develop few, if any tubercles. 
Plants in poor soil stand in closer symbiotic relations with the 
Rhizobia. 
Frank's conclusions in regard to Pilzsymbiosis as they appear 
in Heft 7, 1891 of the “Berichte der Deutschen Botanischen 
Gesellschaft” may be briefly summarised as follows: 
1. Endotrophic mykorhiza is found in roots of Orchids, 
Ericacez and other plants. 
2. In the Orchids the mykorhiza consists of a collection of 
yellowish interwoven septate hyphe, generally found in epidermal 
cells of the root or rhizome. 
3. The fungus during its whole life-course lives within the 
root cells of the host. 
4 Nuclei of infected cells become much enlarged, showing an 
increased activity of cell protoplasm. 
5. The living protoplasm ot the root cells absorbs the proto- 
plasm of the fungus. This is observed in roots that approach the 
period of decay. 
on The fungus is at first nourished by the cell protoplasm, 
which changes it so as to render it unable to grow outside of the 
root cell. 
In regard to the mykorhiza of Ericacee, Frank comes 
