By Edward Solly, Esq. 



53 



they feed, that the growth of the former, must, to some extent, be 

 dependent on the quantity of inorganic matter contained by the 

 latter. This conclusion, if born out by experiment, would lead to 

 a subject of considerable practical interest, namely, the influence 

 which the earthy matters in wood may have on the growth of fungi, 

 and decay of timber. 



The Mistletoe (Viscum album) derives a large proportion of 

 earthy matters from the trees on which it grows. On examining a 

 plant, I found in the leaves 820, in the branches 462, and on the 

 stem 282 parts of inorganic matter ; whilst the apple tree on which 

 it grew contained only 233 parts, in 10000 parts of the dry plants. 

 On examining other parasitic plants and fungi, it was found that 

 in all cases they contained a large proportion of earthy matters, 

 and very commonly far more than the plants on which they grew. 

 Whether the whole of these inorganic substances was derived from 

 the trees on which they grew is questionable, it is by no means 

 impossible that some of it may have been derived from the air. 

 Several fungi contain it is well known a notable quantity of copper, 

 I have in particular found it in the large brown Boletus which grows 

 upon Elm Trees, but I was unable to detect any in the wood or 

 bark of the tree on which it grew. 



The inorganic constituents of Epiphytes were next examined. 

 As many of these curious plants, which grow on the stems and 

 branches of trees, derive nourishment chiefly from the air, and seem 

 to flourish equally well, whether their roots enter the soil, or hang 

 freely in the air ; it was interesting to ascertain what proportion of 

 earthy matters they contained, and whether it varied under diffe- 

 rent circumstances. It appeared probable that the quantity of in- 

 organic matter which they contained would be smaller, than that 

 in most plants, and that the quantity present in those which grew 

 only in air would be less than in those whose roots entered the soil. 

 It was found however that the leaves of Orchidaceous plants contain 



