SOIL FUNGI 277 



Christoph 161 obtained from Calluna vulgaris a Cephalosporium and 

 claimed to have produced the mycorrhiza synthetically; however, his 

 experimental work is open to criticism (Rayner). 162 Ridler 163 isolated 

 from Pellia epiphylla a fungus which also belonged to the genus Phoma. 

 Huber 164 isolated from Liparis laeselii a Rhizoctonia (R. repens). A 

 species of Rhizoctonia (R. apocyanacearum) was also isolated from 

 Vinca minor by Detemar. 165 The fungus grows in the root in all direc- 

 tions, except the endodermis, both inter- and intra-cellularly. When 

 the fungus penetrates into the cells, the starch content even of the 

 neighboring cells begins to decrease. Infection of the plant can take 

 place all the year around, but especially in March to May. 



The organism studied by Detemar forms a special type of endotrophic 

 mycorrhiza, termed "plasmoptic-mycorrhiza." This is clue to the fact 

 that some of the fungus cells undergo plasmoptysis as a result of certain 

 antibody formation by the plants following the infection by the foreign 

 fungus. This process is a step towards the assimilation of the fungus 

 plasma by the plant. Vinca minor is obligately mycotrophic, two-thirds 

 of the root system being infected with the fungus. The fungus can be 

 readily grown on peptone and starch media. 



According to Peyronel 166 the organisms responsible in most instances 

 f or the formation of endotrophic mycorrhiza in phaenerogams, except 

 in the case of the Orchidaceae, form branched or swollen haustoria and 

 are considered to be true Phycomycetes (No. 115, Plate XV). Theo- 

 retical considerations led him to consider these organisms as belonging 

 to a primiti \ e group, which gave rise to the two divergent series, the 

 Phycomycetes and Mycomycetes (Ascomycetes and Basidiomycetes) . 

 That group would also include Endogone, which may represent one of 

 the phases of the biological cycles of the mycorrhizal endophyte. The 

 vesicles of the phycomycetoid endophyte are very likely provisional 

 stores for reserve material. Some of them may change afterward into 



161 Christoph, H. Untersuehungen iiber die mykotrophen Verhaltnisse der 

 Ericales und die Keimung von Pirolaceae. Beih. Bot. Centrbl., 38: H. 2, 115. 

 1921. 



162 Rayner, 1922 (p. 274). 



163 Ridler, W. F. F. The fungus present in Pellia epiphylla. Ann. Bot., 36: 

 193-208. 1922; 37: 483^88, 1923. 



164 Huber, B. Zur Biologie der Torfmoosorchidee Liparis Loeselii Rich. 

 Sitz. Ber. Ak. Wiss. Wien. (1), 130 (Ref. Detemar). 



165 Detemar, K. Uber "Plasmoptysen" Mykorrhiza. Flora, 115:405-456. 

 1923. 



166 Peyronel, 1924 (p. 274). 



