ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 349 



was found growing in the galls of Gapparis. They occur also in galls of 

 Scropliularia canina and Verbascum. In the latter the gall was com- 

 pletely closed and yet lined with the brownish olive mycelium of some 

 fungus undetermined. It is difficult to understand its position if it is 

 of no service to the insect. The author gives a list of all the fungi 

 that have been recorded on galls. 



Origin of Parasitism in Fungi.* — G. Massee winds up his paper 

 by three statements : (1) The entrance of the germ-tubes of a parasitic 

 fungus into the tissues of a living healthy plant depends on the presence 

 of some substance, in the cells of the host, attractive to the fungus. 

 In other words, infection is due to positive chemotaxis. (2) A sapro- 

 phytic fungus can be gradually educated to become an active parasite on 

 a given host-plant, by means of introducing a substance positively 

 chemotactic to the fungus into the tissues of the host. By similar means 

 a parasitic fungus can be induced to become parasitic on a new host. 

 (3) An immune plant signifies an individual of the same species as the 

 one on which a given species of fungus is parasitic, but which, owing 

 to the absence of the chemotactic substance in its tissues necessary to 

 enable the germ-tubes of the fungus to penetrate, remains unattacked. 

 The author conducted a series of experiments to verify these statements. 

 He used the expressed juice of leaves as culture solutions, and tested the 

 presence of the chemotactic substance by sowing fungus spores on a 

 mica film in which a hole had been bored and placing it in contact with 

 the juice. If the chemotactic substance were there, the germinating- 

 tube of the spore grew towards the hole. He also found that the 

 chemotactic property could be destroyed by the addition of certain 

 reagents, such as a trace of acetic acid, etc. In order to educate a plant 

 to become host to any parasite, he injected into the tissues some 

 substance chemotactic to the fungus. Thus he induced Penicillium to 

 invade the leaves of Tradesccmtia discolor by injecting into it a solution 

 of cane-sugar. Other saprophytic species were induced to become 

 parasites on Begonia leaves by the same method, and after 15 generations 

 they grew as parasites without any addition of a sugar solution. 



Fungi of Kew Gardens.f — A long list representing 378 genera and 

 1762 species of fungi has been compiled by G. M. Massee. This 

 abundant flora for such a small area is partly explained by the continual 

 introduction of new plants and new soil from all over the world. Many 

 of the species are exotic and grow in the greenhouses ; others grow as 

 parasites on foreign plants. Massee states that no parasitic fungus 

 destructive to plants has been introduced to Europe through Kew. The 

 special habitat of each plant is given, and the poisonous or edible species 

 among the larger fungi are indicated. The list includes the Mycetozoa. 



Systematic Notes. — E. J. Durand $ gives a complete account of 

 Peziza fusicarpa, which he places in the genus Macropodia ; he quotes 

 a large synonymy, thus bringing into order a series of names. He places 

 Peziza semitosta in the same genus. A. P. Morgan § continues the 



* Phil. Trans. Roy. Soc, Series B, cxcvii. (1905) pp. 7-24. 



t Kew Bull., add. ser. v. (1906) pp. 103-87. 



\ Joum. Mycol., xii. (1906) pp. 28-32. § Tom. cit., pp. 1-9. 



