180 



attack of insects, aud wo sbouki take beed of these signs of premature 

 decay, and not hope to escape loss of time and expense by endeavors to 

 compel new plants to grow where the conditions have proved unfavora- 

 ble. The Scotch pine itself has in some soils been affected by the malady 

 above noticed, and from the presence of the mycelium of a fungus — the 

 Trametcs radidperda in the liber and in the wood aud roots — a writer 

 has inferred that this is the cause of the injury. ^ But fungi, as well as 

 insects, seldom attack wood until decay has begun, for it is in putrefac- 

 tion that they find the nutriment essential for their development. We 

 ueversee a vigorous-growing tree thus affected, aud whenever these signs 

 of disease appear, it is safe to conclude that the tree is on the decline. 

 They should therefore be regarded as a notice to the sylvicultnrist that 

 some of the conditions essential to life are wanting. These views of the 

 cause of the maladie duroud may perhaps be criticised, yet they are not 

 mere hypotheses, but are founded upon facts. 



[In many parts of the Northern States the Norway spruce (Ahies ex- 

 ceJsa) after starting with great vigor, and growing twenty years or more, 

 has lost its thrifty growth, and showed signs of maturity and decay, not 

 unlike that noticed in the Pinus pinaster and P. sylvestris above described. 

 It is reasonable to suppose that this may be from a similarcause, although 

 no direct evidence has been shown. The conclusion, however, is quite 

 obvious that if one species will not succeed in a given locality another 

 should be tried. While instances may occur in which an exotic species 

 may thrive with exceptional vigor, it is always safe to consult the evi- 

 dences of capability shown by native timber-trees, and proper to adopt 

 for planting those that have i)roved themselves capable of good results.] 



EUST IN YOUNG- PINE SEEDLINGS. 



There is another special malady of the Pinus sylvestris, P. larico, etc., 

 unfortunately too common, the " rust of the pine" which frequently 

 attacks the young plants of these kinds, and which develops a para- 

 site, the Aecidium pini (Per.-*.), the history of which we will give : 



The A. pini (Pers.) belongs to the fungi, of the tribe of the uredines 

 (rusts), the alternate generation of which has been finely demonstrated 

 by the researches of M. de Bary ; but we have never yet been able to 

 detect its intermediate states, nor the plants of which it is the parasite. 

 We know it only in one of its forms, the A. pini, a parasite of the P. syl- 

 vestris and its allied species. The mycelium of this fungus is developed 

 m the needles, bark, and wood — colorless at first, and growing red to- 

 ward the points from which it is about to produce the exterior organs of 

 reproduction. The growths appear on the surface of the needles of the 

 plant when two or three years old, and on the bark in the form of little 

 yellowish brown or golden yellow spots. Plantations three to ten years 

 old are especially liable to the rust, which becomes always less for- 

 midable as the plant increases in age. It is rare on pines twenty to 

 thirty years old, and instead of attacking the whole of the top, it gen- 

 erally concentrates itself on some of the branches. It does not neces- 

 sarily kill the plants attacked, but still its persistence may work the 

 complete loss, and it often proves a real calamity in nurseries of this 

 species. Wo must not confound this disease with that which some- 

 times appears in pine seed-beds in the spring-time, in which the young 

 plants become red, and often die. This is supposed to be due to a cli- 

 matic cause, aud will be more fully considered in another part of this re- 

 port. 



' M. d'Ai-boia de Jubainville. 



