466 



FUNGI IMPERFECTI. 



stricted tissue will be found extending quite round the twig 

 (Fig. 293). At these places the bark and cambium have been 



killed, whereas the higher 

 portions of the twig have 

 continued to increase in 

 thickness. Numerous 



small black pycnidia 

 break out on the bark 

 of diseased places and 

 give off small unicellular 

 spindle-shaped conidia, 

 which convey infection 

 to new hosts in August 

 or September. Killed 

 branches die and dry 

 up without casting their 

 needles.^ 



Ph. pithya Sacc. 

 causes a disease similar 

 to the preceding on the 

 Douglas fir {Pscmlotsuga 

 Douglasii). The pycnidia 

 of the fungus are found 

 on dead constricted parts 

 of twigs, and they, as well 

 as other symptoms of the 

 disease, closely resemble 

 those of Phoma abietina. 

 Tiostrup" defined and de- 

 scribed it as Ph. intliya 

 Sacc, Magnus also re- 

 cords it on branches of 

 Pinus sylvestris in Berlin 

 botanic garden. 

 Other species of Phoma frequent other conifers and broad- 



Fi<i. 203.— P/tojurt abietina. Twig of Silver Fir sh 

 ing tlie constriction characteristic of this disc; 

 dotted over witli pycnidia. (After R. Hartig.) 



I ^ Bohni (Zcitsch. f. For.st- u. Jagd-ioesen, 1896, p. 154) describes and figures 

 iin attack of this parasite on Pseudotsuga Douglasii in North Germany. One 

 cannot, however, avoid suggesting some confusion between this and Ph. pithya, 

 described next. (Edit.) 



'■'E. Rostrup Undersopgelser over Snyltes i-ampes Anareb paa Skovtraeer, 

 1883-1888. 



