NOTES AND ABSTRACTS 



135 



series the water was aerated, in another treated with dry calcium car- 

 bonate, in another shaken with lampblack and filtered ; other sets were 

 grown in the untreated bogwater and in an extract (4 gm. of bcgsoil in 

 400 ccm. of distilled water). 



The experiments point to an injurious effect of some water-soluble 

 substance in the bogwater which can be corrected by a method of aeration 

 and by the use of calcium carbonate and lampblack. This is more 

 marked in the sphagnum than in the maple-alder zone. 



Those plants which grew in the bogsoil extract were stunted in root- 

 formation, whilst their leaves were reduced in area, thicker, and with 

 revolute margins — that is, distinctly xerophilou3 in character. This he 

 explains as due to a reduced transpiration current in consequence of the 

 poisonous character of the soil. The beneficial effect of small doses of 

 poisons comes out in some of the CaC0 3 and carbon-black solutions. 

 Phaseolus seedlings grown in these closely resembled similar cultures in 

 a -0001 strychnin or atropin sulphate solution. The width of the annual 

 rings of wood in Acer rubrum, both from the ordinary woodlands and 

 from the bog island zone already mentioned, was measured and tested 

 biometrically. The mode was 3 mm. width from the bog island, and only 

 2 mm. from the ordinary woods. There were also very marked differences 

 in mean, standard deviation, and coefficient of variability. The author 

 seems to explain this also by the stimulation due to minute proportions 

 of poisonous solution in the bogwater. 



We find, however, the following sentence : " It may be readily ques- 

 tioned whether part of the response arises from a deficiency cf oxygen in 

 the soil." This, of course, is the usual explanation of the peculiarities of 

 peat-floras, but whether the author means by this sentence to admit this 

 explanation or not is not particularly obvious. — G. F. S.-E. 



Pecan, Cultivation of. By Prof. H. S. Van Deman (U.S.A. Stn. 

 Sort. Soc, Louisiana, Ann. Bep. 1908 ; pp. 18-94). — The author considers 

 the pecan to be the most valuable orchard tree for cultivation in Louisiana. 

 He recommends that they should be grown one hundred feet apart and 

 cotton, Irish potatos, or corn grown between them. — F. J. C. 



Pentadesma Kerstingii. Seed of. Not. Kdnig. Bot. t Berlin, 

 No. 44, p. 102). — These seeds are rich in fat. — 8. E. W. 



Pinus Bungfeana (Bot. Mag. tab. 8240). — Nat. ord. Coniferae ; 

 tribe Abietineae ; North China. Tree 60-100 feet high, crown pyramidal 

 or ovoid ; leaves in threes ; cone when mature H-2 inches long ; scales 

 rhomboidally thickened at the tips. — G. H. 



Pitophora. By A. Ernst (Ann. Jard. Bot. Buit., vol vii., pp. lS-oo ; 

 4 plates). — The growth, development, and structure of Pitophora 

 sumatrana are described. — S. E. W. 



Plants containing- Cyanogen derivatives. By A. W. K. 



De Jong (Ann. Jard. Bot. Buit., vol. vii., p. 1-17). — The leaves of 

 Pangium edule contain the glucoside gynocardine, which is also present 

 in the seeds of Gynocardia odorata. The glucoside is decomposed by the 



