NOTES AND ABSTEACTS. 



885 



tints that are only apparent upon a closer view. Several varieties may be 

 called snow-white, such, for instance, as 'Baronne de Meynard,' ' The Queen,' 

 'Frau Karl Druschki,' 'Katharina Zeimet,' and ' Anna Marie de Montravel,' 

 these last two being dwarf Polyantha Roses. Then comes the section of 

 flesh-white Roses, headed by the 'Hon. Edith Gifford,' a splendid Rose 

 which gains in popularity every year. ' White Lady ' is magnificent, 

 1 Augustine Guinoisseau ' and ' Souvenir du President Carnot ' are 

 excellent, and ' Marjorie ' is a little gem. — E. T. G 



Roses, Yellow Banksian. By E. H. Woodall {Garden, No. 1728, 

 p. -147; 31/12/1904). — When grown on a sunny and sheltered wall in 

 favourable positions, this fair climber attains to much beauty in England ; 

 but even then it is not every year that it is permitted to adorn itself with 

 its butter-gold rosettes of clustering flowers. Those who wish to realise 

 the full luxuriance and beauty it is capable of must travel further afield 

 and see it in Italy or on the Riviera, where it often smothers a tall tree 

 with its growth and hangs down, a tangle of golden glory, from a height of 

 40 feet or more, that puts to shame the puny endeavours of less sunny 

 climates. How much do we not owe to those who brought it from its 

 Eastern home ! The pretty single yellow form, presumably the wild type, 

 was not introduced till comparatively lately. It has the merit of even 

 greater vigour and luxuriance, and is quite a fortnight earlier than the 

 double form.— E. T. G. 



Root Pressure in Trees. By Alfred J. Ewart (Ann. Bot. xviii. 

 Jan. 1904, pp. 181-182). — A note dealing with observations made on two 

 Elm trees which had been cut down. The following questions are suggested 

 as lines for future research : — (1) Does the total resistance to the flow 

 of water in the trunk of a deciduous tree vary, and show an annual 

 rhythm or periodicity ? (2) Is the root-pressure comparatively constant 

 throughout large root systems, and do all regions of such systems awaken 

 an active absorption at the same period of time ? — A. D. C. 



Roots : Are Roots Aerotropic ? By M. E. Bennett (Bot. Gaz. 

 xxxvii. No. 4, p. 241). — Miss Bennett experimented with several plants 

 and in various ways, presenting 0, C0 2 , H, &c. on one side only. 

 Negative conclusions were arrived at. " Definite direction curvatures are 

 not induced in roots by the one-sided access of such gases as mentioned, 

 and roots are therefore not aerotropic." — G. H. 



Roots, Geotropy in, Starch-grain Theory of. By B. Nemec 

 (Beih. Bot. Cent. xvii. pp. 45-60, with 1 plate). — Gives several experiments 

 and answers various criticisms by Czapek, Wiesner, Noll, and others with 

 regard to the above theory. He cut off pieces '5 mm., 1 mm., and 1*5 mm. 

 long from the root tips of Lupinus albus, and found in seven hours a 

 clear curvature in the first lot (*5 mm.), whilst the others were not curved. 

 In twenty hours the 1 mm. set showed a clear curvature, and it was 

 found on sectioning that cells with starch-grains had been formed. Those 

 with 1*5 mm. cut off showed no curvature. The use of glass caps leads 

 to compression and possible deformation of the perceptive zone. Even 



