420 SUMMABY OF CURRENT RESEARCHES RELATING TO 



raent of a beautiful red colour around the wound due to the formation 

 of a red pigment in one or more of the layers of the cells of the bark. 

 Dr. Beyerinck believes that the fungus produces a fluid of the nature 

 of a ferment, which penetrates the adjacent structures, since the 

 disease extends beyond the parts in which any trace of the fungus can 

 be detected. This ferment he believes to act on the cell-walls, starch- 

 granules, and other constituents of the cells, transforming them into 

 gum, and even changing into gum the Coryneum itself. The influence 

 of this fluid is also exerted in the cambium, causing the formation of 

 morbid parenchyma, the cells being cubical or polyhedral, thin-walled 

 and rich in protoplasm, which is in its turn transformed into gum. 

 It is further stated that " a similar disease produces gum arable, gum 

 tragacanth, and probably many resins and gum resins." Gum traga- 

 canth is known to be produced by the pith as well as the bark of the 

 stem, and to ooze out from the pith when the stem is cut ; and if it be 

 indeed due to a disease it would seem as if the disease infects the 

 whole plant. Gum, moreover, may be found in the uninjured husk of 

 the almond, and it seems at first sight more probable that the irritation 

 caused by a fungoid parasite should cause a greater flow of the natural 

 product, just as the irritation caused by an insect causes the develop- 

 ment of galls. 



Attraction of Insects by Phallus and Coprinus.* — E. Eathay and 

 B. Haas have examined the structure of the fructification of Phallus 

 impudicus, with a view to determine the peculiarities in its construc- 

 tion which attract flies and other insects to it. This is effected partly 

 by the odour and partly by the taste. They find the fluid which results 

 from the deliquescence of the gleba to contain abundance of sugar ; 

 and visiting this they observed as many as fourteen species of insect, 

 most of which also visit the nectar of flowers or feed on honeydew. 



The same phenomenon is exhibited by a number of other species 

 of Phalloidese ; and the explanation suggested is that the insects are 

 useful to the fungi in disseminating the spores, which are set free by 

 the deliquescence of the gleba. 



The pileus of species of Coprinus and of some other species of 

 Agaricini also exude sugar. 



With regard to the exact chemical nature of the substance 

 formed, the authors state that it consists in all these cases, in addition 

 to dextrose, of another sugar which also belongs to the same class, 

 and is probably trehalose. In Phallus impudicus there are no less 

 than three substances which reduce alkaline solution of copper, viz. 

 dextrose, levulose, and a substance intermediate between dextrose and 

 gum. In Coprinus deliquescens the only one of these substances present 

 is dextrose. 



Development of Ascomycetes.t — After some further details of 

 the points in the development of the Ascomycetes already alluded to, 

 E. Eidam describes two other remarkable species. 



* SB. K. Akad. Wiss. Wien, Ixxxvii. (1883) pp. 18-44. 



t Cohn's Beitr. Biol. Pflanzen, iii. (1883) pp. 877-433 (5 pis.)- Cf. this 

 Journal, ante, p. 94. 



