44 EXPEPtTMEXT STATION EECORD. 



spruce wlicrcvcr itDssildc. ,is well :is to jjcet the best results Iroiii 1li<' lir. Oliser- 

 vatiniis were luiide :is to llie toler;iiice. power of reeovery .il'ler suppression, 

 resistance to windfall, soundness at different ages and under different condi- 

 tions, and rapidity of growth of fir as compared with spruce. 



Fir was found to be less tolerant than spruce, and especially subject to wind- 

 fall in north central Maine after a diameter of 15 in., breast high, is reached. 

 In a piu-e stand tir is subject to rot at the butt after the age of 50 j'ears, par- 

 ticularly in moist situations. When mixed with hardwoods the percentage of 

 rot is said to l)e smaller and the trees are usually sound up to an average age 

 of 85 years. 



After windfall in a pure spruce flat or slope, a pure stand of tir follows, 

 whereas on lowland areas, under normal conditions, the flr occupies less than 

 5 per cent of the stand, with an increasing percentage on upward slopes. After 

 windfall in a spruce stand containing hardwoods, a stand predominantly hard- 

 woods and fir results. On mixed hardwoods and spruce slopes the projrortion 

 of fir is doubled after each cutting. When the cut is too heavy tlie tir will 

 surpass the spruce in the next generation. 



In conclusion the authors state that although the fir is seen to be more abun- 

 dant in the young growth after cutting, it is probable that in many cases it will 

 eventually die out and its place be taken by the spruce. While the fir is 

 growing, however, it is not only retarding the spruce but occupying space, and 

 thus causing just so many years" loss of growing time to the spruce. 



Hevea brasiliensis in Singapore, R. Schlechter (Tropenpflaiiser, 11 (1907), 

 No. 3, pp. 133-1-il). — An account of the Hevea plantations of the botanical 

 gardens of Singapore, dealing with the constitution of the stands, production 

 of seed, and methods of harvesting the Hevea, together with a discussion of 

 pure stand planting versus companion crop planting. The author believes that 

 the attempt to keep down harmful weeds in pure stands is too costly, and sug- 

 gests the use of cover crops, reconnnending such species as Passiflora foctidri, 

 Crofolaria xtricta. and one of the Tephrosias. which will not only keep down 

 liarmful weeds but add plant food to the soil as well. 



Where comi>anion crops are desired admixtiires of cacao, coffee, tea. peanuts, 

 tapioca, .-ind ui)land rice are recommended for different situations. 



Latex and rubber of Parameria glandulifera from India (Bui. Imp. Inst., 

 ■') (1901), No. 1, pp. I'l-Ui). — This brief article states that Parameria fjlaiidii- 

 lifcra, a climbing plant, is distributed through southern Burma, Indo-China, and 

 the ]Malay Peninsula, and has long produced a yield of good rubber, which is 

 exploited by the native collectors. Samples of the latex and rubber of this 

 plant have been forwarded to the imperial institute from Burma and the 

 Andaman Islands, and the dry rubber was found to contain 91.8 and 91.G per 

 cent, respectively, of caoutchouc. In each case the percentages of resin and 

 in-oteids are low and the rubber is free from vegetable impurities. 



DISEASES OF PLANTS. 



Studies in the inheritance of disease resistance, K. II. Biffen (.Jour. Af/r. 

 Nc/.. .> (1907). Xo. 2. pp. 109-128). — ^While studying the inheritance of certain 

 characteristics of wheat the author was letl to believe that possible liability and 

 immunity to attacks of yellow rust were paired characters, and experiments 

 were inaugurated to determine on an extensive scale whether immunity to 

 attacks of different fungi might be transmitted in the usual Mendelian way. 



The experiments consisted in crossing a number of varieties of cereals and 

 lesling their resistance to yellow rust, black rust, and a mildew of cereals {Hrij- 



