142 ASCOMYCETES. 



The Slime- or Mucilage-fluz of Trees. 



This is a very common phenomenon in our avenues, parks, 

 and forests. It can be observed during the period of vegetation 

 on several species of trees, particularly on spots woimded by 

 removal of branches, by frost rupture, or by some other cause. 

 The wound may, however, be so grown over or occluded that 

 at first sight the slime appears to flow from the uninjured 

 bark. These slime-fluxes are very common on dead branch- 

 snags and in places affected with sun-stroke or frost- wounds; 

 while I have frequently found them on dead tree-stools 

 and on wooden water-pipes where the water trickled from 

 some fissure. It is thus probable that they are always 

 produced on the site of some wound, although Ludwig, 

 without giving any details, says that there may be no previous 

 injury. I have never observed any case where a tree with a 

 slime-outflow became sickly and died, and the cases of death 

 recorded by Ludwig are probably due to some other cause. 

 Ludwig, however, says decidedly that the white slime-flux on oak, 

 as well as the brown flux of apple, horse-chestnut, and 

 others, are really parasitic phenomena. I must say, however, 

 that I have carefully examined the occluding tissues on frost- 

 cracks showing slime-flux, and found them quite healthy. 



The white slime-flux of the oak.^ 



According to Ludwig, the white slime-flux of the oak and 

 other species of trees takes place during moist weather, and 

 from June to September. It flows from branch-scars, former 

 frost-ruptures, and other wounded places ; also from apparently 

 uninjured bark. Ludwig believes that such wounds are infected 

 by the agency of insects, particularly hornets ; that the disease 

 spreads through the bark and breaks out in various places. On 

 such spots the edges of the wound are alternately occluded 

 and killed again, so that a flux-wound may come in course of 

 time to resemble a "canker-spot." Large areas of the bark die off, 

 and the death of the wood frequently follows. 



1 Ludwig : (1) " Ueber Alkoholgiihrung u. Sohleimfluss lebender B&ume u. dereii 

 Urheber." Ber. d. deutsck botan. Ges., 1886. (2) "Ueber profuse Guminose d. 

 Eichen a. welter. Mitth. iib. Alkoholgahrung u. Sohleimfluss lebender Baume." 

 Oentrbl./. Bakt. u. Parasitenkunde, 1890. (3) Le?irbuch, 1892. (4) Forst.-natw- 

 wiss. Zeitschr., August, 1894. 



