i'ii SUMMARY OF CURRENT RESEARCHES RELATING TO 



study was mainly occupied with an account of the root fungi. These- 

 were present on the roots of the one-year seedlings, the hyphae filling 

 the cells of the cortex, recognisable externally by the darkening of the 

 rootlets and by a slight increase in thickness. This endotropic fungus 

 was thrown off with the development of the periderm. The root then 

 becomes enveloped with the ectotropic mycorhiza. The tips of the 

 main roots are free from the fungus. The writer discusses the probable 

 species of fungus that provides the mycorhiza. He does not think it 

 can arise from Mucorini. He also deals with the subject of nitrogen 

 assimilation by the plant. 



In connection with the same subject, F. TV. Neger * has reviewed! 

 Stahl's experiments with plants in sterilised ground — with regard to the 

 competition for nitrogen that is supposed to be aided by the presence of 

 mycorhiza. Stahl held that plants which were always independent of 

 mycorhiza would grow better when no hyphae were present to exhaust 

 the nitrogen of the soil. Neger finds that the more successful growth 

 in sterilised soil must have been clue to favourable chemico-physical 

 conditions, and not to the absence of fungus hyphae. 



Nutrition of Fungi by Carbohydrates.f — M. Nikolski gives a. 

 historic review of previous work on this subject, and then states the pro- 

 blems he tried to solve, viz. the behaviour of filamentous fungi with 

 regard to carbohydrates as nutriment. He experimented with Amylo- 

 mypes, and states his methods of culture and examination. A long list 

 of experiments follows, and the general results are summed up. Maltose 

 was assimilated with much rapidity. Glucose and saccharose came next, 

 and a long way behind galactose, fructose and rafinose. 



Inulin proved to be the best medium as regards nutrition. Various 

 changes are due to the age of the fungus, and periodicity of growth 

 is noted depending on the different carbohydrates. 



The final portion of the work deals with the formation of nitro- 

 genous substances by the fungus, which is correlated with its development. 

 After the maximum of growth is reached, nitrogen formation ceases. 



Artificial Parasitism4 — G. J. Pierce has succeeded in growing a 

 pea-plant on a plant of Vicia Faba. The radicles of young seedlings 

 were inserted into holes cut into the stem of strong young bean-plants, 

 and fixed in place by a mould of plaster of Paris. The pea-plants, 

 though smaller in size than usual, blossomed and formed seeds capable 

 of germination. Comparing the sizes and weights of the seeds with 

 the sizes of the plants, the author found that the individual seeds were 

 much less reduced in size and weight by the enforced semi-parasitism 

 of the parents than were the vegetative parts. Seeds of plants grown in 

 this artificial manner were successfully germinated in sphagnum moss. 

 and transferred to bean-plants. They formed healthy plants, but some- 

 what smaller than those of the previous season. There was no true 

 union between the root of the pea and the tissue of the "host." The 

 roots grew downward through nodes and internodes, but did not in any 



* Nnturw. Zeitschr. Land, mid Forstw.. i. (1<K)3) p. 372. See al.-o Centraibl. Bakt., 

 xi. (1903) p. ::; f < eutralbJ. Bakt . xii. (I'.i04) pp. E54-£>, 656-75. 



X Bot. Gazette, xxxviii. (1904) pp. 214-7. 





