NOTES AND ABSTRACTS. 



615 



the spray depends upon the percentage of arsenic present, but that 

 the amount of fruit caused to drop through the spraying depends upon 

 the form used rather than upon the amount of arsenic present, the 

 acid form being the worst. — F. J. C. 



Bamboos, Climbing. By Miss Agnes Chase (Bot. Gaz. Iviii. 

 pp. 277-279, Sept. 1914 ; I plate). — Gives some interesting field 

 notes on Arthrostylidium and other climbing bamboos of Porto Rico. 

 A. sarmentosum is " a most airy, graceful, delicately beautiful species, 

 the long, slender vine-like culms, with their clusters of pale-green foliage 

 festooning the trees, or hanging free from the long limbs above a 

 trail or rivulet and suggesting a lacy veil." This species is excep- 

 tional in the stems dying down each year. The author found it in 

 full flower on Dec. 2, 1913. 



A . muUispicatum has the slender, naked, growing ends of the culms 

 beset with short, sharp prickles. These long grappling branches 

 swing in the breeze like a whip-lash until they strike a hold. These 

 branches are freely produced, and form an inextricably entangled mass 

 that draws blood at every step of one's progress through it. — G. F. S. E. 



Black Spot on the Mandarin {Agr. Gaz. N.S.W. vol. xxv. p. 684). 



— When a Mandarin orchard is attacked by black spot, the trees should 

 undergo a drastic pruning. Immediately after pruning, the trees and 

 soil beneath must be sprayed with Bordeaux or lime-sulphur mixture, 

 also after the fruit sets, and again a fortnight later. — S. E. W. 



Bordeaux Mixture, The Action of, on Plants. By B. T. P. 



Barker and C. T. Gimingham {Ann. Appl. Biol. i. pp. 9-21 ; May 1914 ; 

 figs.). — In connexion with investigations into the action of Bordeaux 

 mixture, observations, which are here recounted, have been made upon 

 spray injury or " scorching " by Bordeaux mixtures and the penetra- 

 tion of copper from Bordeaux mixtures into the plant. The authors 

 found that cells with readily permeable walls, such as the germ tubes 

 of fungus spores, root hairs, the interior tissues of leaves, &c., exert 

 a considerable solvent action on the particles of copper compounds 

 with which they come into contact. The dissolved copper is rapidly 

 absorbed and the cells killed, such action, in the case of injured foUage, 

 resulting in scorching. The extent of interaction between copper 

 compounds and other types of cells depends upon the nature of the 

 cell wall. Direct absorption of copper by leaves of certain types takes 

 place with or without local injury, and may have a marked effect upon 

 the colour of the fohage. Potatos, beans, and other plants also absorb 

 copper by their roots with local injury to them, and the absorbed 

 copper can be translocated to the aerial parts of the plants without 

 injury to the cells through which it passes. — F. J. C. 



Botanic Gardens at Rio de Janeiro. By R. C. McLean {New 

 Phyt, vol. xii. Nos. 9-10, pp. 336-342). — The author gives a brief 

 but interesting description of the large botanic gardens at Rio de 

 Janeiro, and of the forest and other types of vegetation in the 



