SECTIONAL TRANSACTIONS.— K. 4K 



Mr. C. G. C. Chesters and Mr. C. J. Hickman.— Root and stem diseases 

 of the cultivated Viola (11.25). 



The paper deals with the increasingly serious root and stem infections 

 of Viola due to fungi belonging to the following genera ; Pythium, Asco- 

 chyta, Mycothecium and Rhizoctonia and describes the field symptoms of 

 the diseases caused. The necessity of recognising the causal organism of 

 certain diseases is emphasised in relation to the control measures to be 

 adopted. Certain morphological characters of the parasitic fungi are 

 described— especially in the case of the species of Pythium and Ascochyta. 

 The most usual species of Pythium isolated from diseased viola plants 

 differs from species of this genus already described— it is tentatively recog- 

 nised as a new species- 

 Mr. J. S. L. Gilmour. — Whither taxonomy? (n.50). 



With the development of genetics, cytology and ecology, thirty or forty 

 years ago, taxonomists began to realise that, if a system of classification 

 was to reflect accurately the true structure of the plant kingdom and 

 to form an adequate vehicle for further progress, its basis must be 

 widened to include the facts revealed by these new sciences. A number 

 of taxonomic studies accordingly began to appear on these new lines, side 

 by side, of course, with a continuation of the old type of work based solely 

 on morphological and distributional data. To-day these two streams of taxo- 

 nomic activity have partially separated out into what have been conveniently 

 called the ' alpha ' (or old) and ' omega ' (or new) taxonomy respectively. 

 What of the future ? 



It will be generally agreed that, while ' alpha ' work is still essential, 

 especially for little-known floras of which only herbarium material is available 

 for study, ' omega ' methods can be fruitfully applied to well-known floras 

 of which ample material exists for cultural, genetical and cytological work. 

 The author puts forward the view that these two streams should be much 

 more clearly separated than at present if they are not to interfere with each 

 other to their mutual disadvantage. He does not, of course, advocate 

 non-co-operation, but, rather, full recognition of the different concepts and 

 terminology involved in the two taxonomies, and, if possible, the attainment 

 of a measure of agreement between taxonomists, geneticists, cytologists 

 and ecologists on a common basis for further ' omega ' progress. 



Mr. A. G. Lowndes. — Flagella movement (illustrated by a cinematograph 

 film) (12.20). 



By means of high-speed cinema photomicrography it has been possible 

 to prove the following : 



(1) The waves are propagated along the flagellum of Peranema from the 

 base to the tip and not in the opposite direction. 



(2) The waves are propagated along the flagellum with an increase in 

 velocity and also an increase in amplitude, and hence the flagellum cannot 

 be obtaining the whole of its energy from the cell. In other words the 

 flagellum is not a passive unit mechanically operated by the cell. 



This has finally answered a question over which there has been con- 

 siderable controversy. 



(3) Four other species of uniflagellate organisms have been investigated 

 by the same method and the same conclusions are to be drawn. 



(4) The distinction between a pulsillum and a tractellum is not really 



p 2 



