284 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



Each parasitic tubercle consists of bark, sclerenchyma masses, and 

 some cellular tissue belonging to the host, and cellular tissue and bundle 

 tissue, chiefly developed in flower stalks, of the parasite. Stomata present 

 over the flowering shoots, but absent from the leaves, which latter are 

 brownish-leathery when mature, and devoid of palisade tissue. Cells of 

 leaves and young shoots contain refractive bodies, which may be of a 

 glucoside character. The flowers show a small ovarian nectar gland. 



M. C. C. 



Effects of Copper on Fungi. 



Copper Compounds, Toxic Properties of, with special refer 

 ence to Bordeaux Mixture. By J. F. Clark (Bot. Gaz. xxxiii. No. 1, 

 p. 26 ; with 7 figs.). — The object was to determine more exactly the con- 

 centration of the various copper compounds required to inhibit germina- 

 tion, or to kill the spores of a fairly large and quite representative selection 

 of fungi. Copper is surpassed in toxic properties by several other sub- 

 stances, but its superiority lies in its cheapness, its adherence to foliage, 

 and its solubility by substances of cell sap, especially that of the parasite. 

 The tables show the results of the toxic effect of sulphate of copper on 

 fifteen fungi, with and without additional substances. 



With regard to Bordeaux mixture Swingle's suggestion that the good 

 effect resulted from the fact that the fungi themselves, by secretions or 

 excretions, might be able to aid in the solution of the copper has been 

 proved to be correct. This power is particularly noticeable in fungi. An 

 infusion of Agaricus campcstris and infusions and decoctions of various 

 parasitic fungi dissolve copper hydroxid very quickly, and in sufficient 

 quantity to inhibit the germination of any fungus tested. The rapidity 

 with which fungus spores are thus killed varies with the character of the 

 contents and coverings of the spores. 



The host-plant is also active in dissolving the Cu(OH) 2 . This zesults 

 from osmosis between the latter when sprayed on the foliage and the 

 juices of the cell sap within the leaf. An important point is that the 

 solution of the copper, whether effected by the host or the fungus spore 

 itself, is possible in the presence of an excess of lime. This excess is 

 apparently somewhat detrimental to the solvent action of the copper, and 

 in this way doubtless serves a very valuable purpose in preventing a too 

 rapid solution. It also protects the Cu(OH)., from the solvent action of 

 the ammonia, nitrites, and nitrates of the atmosphere. The amount of 

 copper necessary for the destruction of the spores of parasitic fungi is 

 probably not more than one part of soluble metallic copper to 80,000 

 parts water (dew). 



As the host-plant has a greater or less power of dissolving the 

 Cu(OH). 2 it may injure them, as in the case of Japanese Plums, Peach, 

 A;c., when sprayed with Bordeaux. — G. H. 



Fungi in Manukks. 



Coprophilous Fung i, Researches on. Bj George Ma isee, F.L.S., 

 and ErnestS. Salmon, F.L.S. (Ann. Bot, vol. XV., No. lviii., p. 314). — The 

 authors remark that until recently the systematic side of mycology had 

 received most attention in Britain ; a fact which probably accounts for the 



