Kelley — 110— Mycotrophy 



Hippophae:— In 1887 Brunchorst spoke of the "well-known" 

 nodules of Hippophae and considered their possible action in fixation 

 of free N. These nodules were rediscovered by Arcularius (1928) 

 who gives a detailed description of their structure and ascribes their 

 formation to a fungus. There is no infection of the vegetative apex 

 nor is starch present in cells infested by the fungus, though abundant 

 elsewhere. The fungal hyphae swell near the cell-nucleus and form 

 "little heads" which gradually swell with a fine, deeply-staining mate- 

 rial. This material is then apparently digested and finally disappears, 

 with coincident nuclear changes. The relation of fungus to host is 

 not obligate, and the author supposed that soil must be inoculated in 

 order to have mycodomatia produced. But Borm (1931) ascribes the 

 nodules to bacteria which, he said, multiply in an enormous way until 

 they fill the whole cell (the nucleus remaining intact) and then diges- 

 tion occurs. 



Gorlaria: — In C. japonica, Katakoa (1930) ascribed N-fixation 

 to the nodules, saying that plants with nodules make vigorous growth 

 while without them growth is retarded. Shibata (1917) said that the 

 endophyte, a typical Actinomycete, forms a rich weft separate from 

 the cortical tissue, the colonies of which in the host-cells have consecu- 

 tive partitions with centripetal pectinate hyphae arranged club-wise 

 about the vacuoles which are filled with cell-sap. The root-nodules of 

 Coriaria in respect to anatomical dififerences surpass all others and 

 its characteristic symbiosis-tissue is quite similar to that of legumes. 



Eucalyptus: — According to Dufrenoy (1922), swellings are 

 found on axes of young Eucalyptus plants, of which the origin is 

 unknown. 



Daucus: — Sterile achenes of carrot were germinated in a mineral 

 gelatine with some addition of glucose (5.0-7.5 parts per 100) and 

 plants were grown in large tubes plugged with cotton; but with 

 glucose there was poor growth. In sterile humus soil with addition 

 of mineral salts, in tubes plugged with rubber stoppers, the air had 

 5 parts per 100 of COg, and the plants grew well, in 40 days forming 

 a tuber 1 cm. in diameter (Molliard, 1920). 



Ericads:— VON Tubeuf (1903) said that on the Chiemsee Moors 

 at Bernau in Bavaria, the largest of the Vaccineae is V. uliginosum, 

 which has its root system deeply sunk in sphagnum. If whole stocks 

 are drawn out of the sphagnum, a portion of the attached roots is 

 obtained with a tender root-work ; while on thin rootlets are found 



