ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 383 



results are printed in tabular form, and provide some interesting 

 reading. He found no difference in the results when ascospores were 

 used for inoculation, and all attempts to infect plants other than 

 Alchemillae were unsuccessful. He concludes that within the biological 

 species Sphserotlieco Hamuli f. sp. Alchemillae there have arisen minor 

 biological species distinguished by the ease or difficulty of infection in 

 the different Alchemilla groups. 



Biology of Botrytis cinerea.* — In spite of all the investigations 

 that have been made on this fungus, many points in its development 

 are imperfectly known. F. L. Brooks has, therefore, examined it with a 

 view to obtaining more exact knowledge. In grape-sugar extract with 

 gelatin the Botrytis developed normally and vigorously. In Kleb's 

 solution, growth was scanty ; on bouillon-gelatin, only microconidia 

 were produced on the conidiophores for the first three generations. In 

 the fourth generation growth was again normal, the fungus evidently 

 having become accustomed to the medium ; no sclerotia, or organs of 

 attachment, were, however, formed in the bouillon cultures. In the 

 infection experiments, lettuce plants were used : the conidia sown on 

 healthy plants produced no effect, but on yellowing leaves, or when the 

 plant was wounded, infection took place. Experiments were also 

 carried out on lettuce plants that had been deprived of certain mineral 

 constituents ; but the results were negative, agreeing with Marshall 

 Ward's experiments on the parasitism of Puccinia dispersa. Brooks 

 also found that starving the host-plant had no appreciable effect on its 

 liability to infection. 



Nutrition of Botrytis cinerea.j — By a series of cultures, Henri 

 Colin has tested the relative value to fungi of the different substances 

 in the Raulin liquid with and without glucose. He obtained the 

 Botrytis by exposing ripe grapes to the air. The fungus would not 

 develop on glucose alone, only some tufts of white mycelium being 

 formed. Various salts were added to the medium, and the results in 

 each case are recorded. As a general result he finds that, though 

 Botrytis does not grow in the total absence of one or other of the 

 substances necessary to its full development, it can utilise them when 

 present in extremely minute quantities. The proportion of each most 

 favourable to its growth has not yet been determined. 



Yeast Fungi .| — F. G. Kohl has published a book which includes 

 the consideration of the organisation, physiology, biology, and sys- 

 tematic account of yeasts and allied fungi. He gives his views on the 

 nucleus of the yeast-cell. In the resting stage it is much like that of 

 other plant-cells, possessing a distinct membrane, nuclear sap, and a 

 crystalloid. Kohl is sceptical in regard to karyokinetic division ; he 

 leans rather to direct division so far as his own observations have gone. 

 Dumb-bell division is constantly to be seen in the budding cells, but 

 the young cell may be quite a large size before it receives its nucleus. 



* Ann. Bot.., xsii. (1908) pp. 472-87 (4 figs.). 



t Eev. Gen. Bot.,xxi. (1909) pp. 97-116 (3 pis.). 



% Die Hefepilze, Leipzig, 1908. See also Bot. Centralbl., cviii. (1908) pp. 611-14, 



