INFLUENCES AND EFFECTS. 229 



tors, if this enemy is less exacting than is the case with the 

 potato, the vine, and the hop. 



Fprestry in Britain is an insignificant interest compared to 

 what it is in some parts of Europe, in the United States, and 

 in our Indian possessions. In these latter places it becomes a 

 matter of importance to inquire what influence fungi exert on 

 forest trees. It may, however, be predicated that the injury 

 caused by fungi is far outstripped by insects, and that there are 

 not many fungi which become pests in such situations. Coni- 

 ferous trees may be infested with the species of Peridermium, 

 which are undoubtedly injurious, Peridermium elatinum, Lk., 

 distorting and disfiguring the silver fir, as Peridermium Thomsoni, 

 B.,* does those of Abies Smithiana in the Himalayas. This 

 species occurred at an elevation of 8,000 feet. The leaves be- 

 come reduced in length one-half, curved, and sprinkled, some- 

 times in double rows, with the large sori of this species, which 

 gives the tree a strange appearance, and at length proves fatal, 

 from the immense diversion of nutriment requisite to support a 

 parasite so large and multitudinous. The dried specimens have 

 a sweet scent resembling violets. In Northern Europe Cceoma 

 pinitorqwum, D. By., seems to be plentiful and destructive. All 

 species of juniper, both in Europe and the United States, are 

 liable to be attacked and" distorted by species of Podisoma t and 

 Gymnosporangium. Antennaria pinophila, Fr., is undoubtedly 

 injurious, as also are other species of Antennaria, which probably 

 attain their more complete development in Gapnodium, of which 

 Gapnodium Gitri is troublesome to orange-trees in the south of 

 Europe, and other species to other trees. How far birch-trees 

 are injured by Dothidea betulina, Fr., or Melampsora betulina, 

 Lev., or poplars and aspens by Melampsora populina, Lev., 

 and Melampsora tremulce, Lev., we cannot say. The species of 

 Lecythea found on willow leaves have decidedly a prejudicial 

 effect on the growth of the affected plant. 



Floriculture has to contend with many fungoid enemies, which 

 sometimes commit great ravages amongst the choicest flowers. 



* "Gardener's Chronicle," 1852, p. 627, with fig. 

 t "Podisoma Macropus," Hook," Journ. Bot." vol. iv. plate xii. fig. 0. 

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