172 



JOURNAL OF THE ROYAL HORTICULTURAL vSOCIETY, 



and Blue-green Algae (phycocyanin) play no active part in the process 

 of assimilation ; that this process is entirely attributable to the chloro- 

 phyll which is always present in Algae and all other plants capable 

 of assimilation; and that the well-known and hitherto generally 

 accepted " chromatic adaptation " theory of Engelmann requires 

 thorough revision, since it does not account for, and is indeed rendered 

 unnecessary by, the results obtained in the author's experiments. 



F. C. 



Pine Blister Rust, White. By P. Spaulding {U.S.A. Dep. Agr., 

 Bur. PI. Ind., Circ. 129 ; June 1913 ; pp. 9-20 ; 6 figs.). — Contains 

 information acquired since the issue of bulletin 206 in 1911 (see 

 R.H.S. Journal, xxxviii. pp. 354-5) . The conclusion that the inspection 

 of diseased plantations recommended in that bulletin might result in 

 the final eradication of the pest has not been borne out by experience, 

 trees which were examined and pronounced sound having been found 

 to be badly affected two years afterwards. The total removal and 

 destruction of diseased plantations is recommended where possible. 

 It has been generally supposed that the rust is carried from one 

 locality to another only by means of infected white pine trees, but 

 there seems sufficient evidence to suppose that the fungus may also 

 be carried on dormant Ribes stock. — A. P. 



Plasmolysis and Distilled Water, Apparent. By W. J. V. Oster- 

 hout {Boi. Gaz. June 1913, pp. 446-451 ; 6 figs.). — ^The author 

 figures and describes protoplasmic contractions of Zostera marina 

 and Polysiphonia when treated with pure distilled water and also 

 with fresh spring water. The process is irreversible. The increase of 

 permeability is supposed to be due to the loss of certain substances, 

 especially inorganic salts. — G. F. S. E. 



Poinsettia, A New Race of {Jour. Soc. Nat. Hort. Fr. Jan. 1913, 

 p. 29). — M. Adnet, of Antibes, is now showing several Poinsettias 

 produced by hybridization. He already has several white ones in 

 cultivation, and as a result of his experiences he believes that this 

 plant, which has hitherto been considered intractably stable in its 

 character, may in the near future be made to show a number of new 

 forms and a wide range of fine colourings. — M. L. H. 



Poison, Alleged Plants of New South Wales. By J. B. 



Cleland {Agr. Gaz. N.S.W. vol. xxv. pt. i. pp. 65-69). — Experiments 

 indicate that the following plants do not poison sheep and calves : 

 Hibbertia diffusa, Omolanthus populijolius (Native Poplar), Indigojera 

 australis, Exocarpus cupressijolius (Native Cherry), Cucumis myrio- 

 carpus, Macrozamia spiralis, and Xanthorrhoea (Grass- tree) . 



5. E. W. 



Poisoning by Conifers {Jour. Bd. Agr. vol. xx. No. 11, p. 994). — 

 Whilst the Yew is the only Conifer which commonly causes poisoning 



