HERPOTRICHIA. 



199 



Herpotrichia nigra Hartig.^ This parasite is distinguished 

 by its grey mycelium, which covers and completely envelops 

 twigs and young plants. On the dwarf mountain pine it is 

 not uncommon to find branches bearing patches of blackened 

 needles closely bound together by gossamer threads, the other 

 parts remaining still green and forming a background against 

 which the blackened masses show up prominently (Fig. 89). 

 Young spruce plants under a metre in height and the lower 

 branches of taller trees are frequently completely enveloped in 

 mycelium, and, where they have been pressed down to the 

 ground by weight of snow, the twigs may be woven round 

 and fastened to the earth by a felt of mycelium. 



\ a 



v^" 



Fig. 90. — Herpotrichia nigra, o, hyphae weav- 

 ing a granular mycelium on the surface of the 

 needle and forming tuber-like bodies over the 

 stomata ; rod-like haustoria are sunk into the 

 outer walls of the epidermal cells. (After B. 

 Hartig). 



Fig. 91. — Herpotrichia nigra, Ascus with 

 germinating spores, (v. Tubeuf del.) 



I have frequently observed the fungus on Jiinipenis com- 

 munis, especially in Bavarian ■forest-land, and on Juniperws 

 nana in the Alps. Professor Peter found it on the latter 

 host in Sweden. 



The spherical dark-coloured perithecia are covered with 

 prostrate hairs, and contain asci with eight four-celled spores. 

 The spores germinate directly to hyphae. The mycelium closely 



'R. Hartig, " Herpotrichia nigra. " Alhg. Forst.-u. Jagd-Zeitwng, 1888. 

 V. Tubeuf, "Mittheilung iib. einige Feinde d. Waldes." AlUg. Forst.-u. 

 Jagd-Zeitung, 1887. 



