TRICHOSPHAERIA. 



197 



asci, the latter with eight four-celled light-grey spores, which 

 germinate directly and distribute the fungus over new host- 

 plants. 



I found this same fungus on Tsuga ca'oadensis^ at Baden- 

 Baden, and on spruces in several parts of the Bavarian forests.^ 

 It, however, rarely attacks spruces, although they often occur 

 in the same forest with iirs. One of the cases of infection 

 referred to above was caused by the diseased branch of a fir 

 lying in contact with a twig of the spruce, so that the mycelium 

 grew from the one to the other ; the spruce needles were kiUed, 

 and woven on to the twig by hyphae. 



Fig. 88. — Trichosphaeria parasitica. Mycelial cushion on lower side of Fir 

 needle, a. Filamentous mycelium, which, at 6, sends downwards numerous 

 branches to produce a cushion of parallel hyphae, c. Where the mycelium rests 

 on the epidermis, rod-like haustoria are sunk into the outer wall of the epidermal 

 cells, e e; d shows the mycelial cushion slightly detached from the epidermis, so 

 that the haustoria have been withdrawn. /' /, Epidermal cells filled with brown 

 contents, g g, Chlorophyllous mesophyll, which becomes brown after the 

 mycelium has penetrated to it. i. Outer court of a stoma filled by a mycelium 

 with no haustoria, but adhering to the waxy granules of the stomatai aperture. 

 (After R. Hartig.) 



In woods of young silver fir naturally regenerated, this fungus 

 causes great damage by killing numerous twigs. It occurs every- 

 where in young fir forests, e.g. the Alps, Bavarian forests, the 

 Black Forest, etc. On dry airy situations, on free-standing 

 trees, and on the highest branches of a tree, it is rarely present. 



^ V. Tubeuf, Beitriige z. Kenntn. d. Bamnkrankheiten, Berlin (Springer), 1888. 

 "v. Tubeuf, "Trichosphaeria parasitica der Fichte." Botan. OentralUatt, 

 XLI., 1890. 



