722 TKANSACTIONS OP SECTION K. 



THURSDAY, SEPTEMBER 9. 

 The following Papers were read : — 



1. Preliminary Observations on the Nature and Distribution of the 

 Statolith Apparatus in Plants. By Miss T. L. Peankeed, B.Sc. 



The term ' statolith ' is used to designate a body free to fall within the 

 cell (the statocyte) which contains it. 



Liverworts show a response to gravity in the disposition of their reproductive 

 organs, which is most marked in the_ gametophores, e.g., Lunularia cruciata, 

 CoTsinia marchantioldes, Plagiochasina italicum, Reboulia hemispherica, 

 Fegatella conica ; and the statolith apparatus shows a striking correspondence 

 in (1) locality, (2) time of appearance, and (3) degree of development. 



Ferns develop a statolith apparatus at the physical apex of young fronds 

 which show negative geotropism. The case of Ophioglossurn vulgatum. 



Certain Monocotyledons which do not ordinarily produce starch nevertheless 

 develop statoliths, e.g., the foliage leaves of Narcissus. 



Seedlings show statoliths in the developing root and stem, even when no 

 starch is contained in the resting plumule or radicle, and when no trophic 

 starch is produced by these young organs. 



The petioles of many foliage leaves possess statoliths which do not disappear 

 when all the trophic starch is dissolved. Special interest attaching to the case 

 of Sagitturia sagitti folia. 



Statoliths seem to be absent from very delicate organs [e.g., some seedlings, 

 Anthoccros sporophyte), from organs in which a geotatic position is of no 

 advantage [e.g., vegetative thalli), and from organs where curvature is 

 impossible. 



The present investigation indicates that — 



Statoliths are often chloroplasts, which may be termed ' chlorostatoliths ' ; 

 e.g., Lunularia, Ophioglossum, Myrio-pJiyllum Proserpinacoides. 



Statocytes may be specialised (1) in shape (as in Polygonum persicaria), (2) 

 in the possession of larger nuclei than the cells of the surrounding tissue (as in 

 Polygonum amphihiurn), and (3) in the behaviour of the nucleus (as in some 

 Pteridophytes). 



The statolith apparatus consists of the whole system of statocytes, which, in 

 Angiosperms, are usually to be found abaxially to the phloem, but may occur 

 singly or in patches in the ground tissue ('diffused type'), or may themselves 

 form a tissue ('complete type'), for which the term ' statenchyma ' has been 

 suggested. 



Modifications and transitional forms occur. The author considers the 

 statolith an intensive mechanism, the simplest form of statocyte being the 

 living cell, which, passing through transitional stages, reaches its highest 

 expression in the cell containing relatively heavy bodies differentiated both in 

 size and mobility. 



2. On the Liquid Pressure Theory of the Circulation of Sap in Plants. 



By Dr. Saeah M. Bakee. 



The two main theories at present current to explain the ascent of sap in 

 trees are the cohesion theory of Dixon and the vitalistic theory upheld by 

 Ewart and Janse. 



A new method of calculating the cohesion of liquids from the latent heat, 

 by a modification of Stefan's equation, shows that cohesion varies inversely 

 with the absolute temperature. Dixon and Joly's experimental demonstration 

 of large cohesive forces in the interior of liquids depends, therefore, upon the 

 increased cohesion caused by lowering the temperature of an enclosed liquid,, 

 and cannot be applied to liquids at constant temperature. 



On the other hand, the experiments of Strasburger and Dixon on the ascent 

 of sap through dead wood have shown that the postulate of the co-operation of 

 parenchymatous tissues in the stem is untenable. 



The present theory is founded primarily upon the ecological evidence that 



