Morphologie etc. — Varietäten etc. — Physiologie. 263 



Cannon, W. A., Some Relations between Root Char ac- 

 ters, Ground Water and Species Distribution. (Science 

 new ser. XXXVII. p. 420—423. Mch. 14, 1913.) 



The author establishes the principles that there may be a very 

 intimate relation between the occurrence of certain species of trees 

 and the character of their roots, having regard to the depth at 

 which perennial water may be found. In the Southwest, trees occur 

 in the streamways; while the nearby upland may be treeless. The 

 humidity of the two areas, the rainfall and the temperature may 

 not be very unlike, but the great difference lies mainly in the soil 

 conditions, particularl}'- with regard to the depth of the ground water. 



Harshberger. 



Corapton, R. H., Preliminary Note on the Inheritance of 

 Self-Sterility in Reseda odorata. (Proc. Cambridge Phil. Soc. 

 XVII. 1. p. 7. 1912.) 



Reseda odorata, as originally proved by Charles Darwin, 

 comprises two kinds of individuals, self-fertile and self-sterile. The 

 present paper reports experiments, as yet incomplete, in breeding 

 self-fertile and self-sterile plants with a view to ascertaining whether 

 the characters in question are hereditary. The results indicate that 

 self-fertility is probably to be regarded as a simple Mendelian do- 

 minant, in whose absence the individuals are self-sterile. Characters 

 of stature and poUen-colour are also being studied. 



R. H. Compton (Cambridge). 



Armstrong, H. E. and E. F., The Function ofhormones in 

 regulating metabolism. (Ann. Bot. XXV. p. 212—219. 1911.) 



The authors emphasise the connection of enzymes with practi- 

 cally all processes of metabolism, their specific nature, and the 

 necessity for some restriction of their action in order to prevent 

 their killing the cells in which their function is to break down 

 complexes. The safeguards existing in the plant to prevent this are 

 illustrated by experiments with leaves which give off hydrogen 

 Cyanide, or which blacken, when exposed to such substances as 

 toluene or Chloroform. Such substances, to which the general name 

 of hormone is applied, serve as activating Stimuli; they are chemi- 

 call}'' inert substances. with but little affinity for water, and they 

 are able to penetrate the cell and bring about hydrolytic changes 

 within it. Various substances which act as weak hormones occur in 

 plants combined with glucose, as the glucosides. One function of 

 gtucosides is to act as hormones when a mild specific stimilus is 

 required; each glucoside requires an appropriate enzyme to hydro- 

 lyse it before its constituents can be effective as hormones. The 

 application of this conception to various problems in plant physio- 

 logy is indicated. F. Cavers (London). 



Blackman, F. F. and A, M. Smith, A new method for esti- 

 mating the gaseous exchanges of submerged water- 

 plan ts. (Proc. Roy. Soc. LXXXIII. p. 374—388. 1911.) 



The plant is enclosed in a glass Chamber, through which a 

 current of water is kept flowing, and samples of inflowing and out- 

 fiowing water are analysed at frequent intervals. The change in 



