Transactions of the London Horticultural Society. 319 



add that Messrs. Loddiges have now (Dec. 1831) above 

 300 species. 



The result of various experiments to ascertain the best soil 

 and climate for these plants may be said to amount to this : ■ — 

 " That a well- drained soil, shade, a very high temperature, and 

 an atmosphere nearly saturated with humidity, are the con- 

 ditions that are requisite to insure their successful cultivation, 

 and that soil itself is of little importance to them. We have 

 used common garden earth, lime rubbish, gravel, decayed 

 vegetable matter, and moss, and all with equal success, pro- 

 vided the drainage was effectual ; and we have found all these 

 equally useless when the drainage was not attended to ; a cir- 

 cumstance which is, no doubt, due to the succulent nature of 

 the plants, and to the very imperfect means that most of them 

 possess of parting with superfluous moisture: in consequence 

 of the compact nature of their cuticular tissue, and of the 

 minute size, or small number, of stomata or evaporating pores. 

 We have found that no soil or temperature would nourish 

 them in drought, and that any soil was good when the tem- 

 perature and atmospheric humidity were carefully regulated. 

 To speak very accurately upon these points, I should say, 

 that the mean temperature of the day ought to be 87° or 

 thereabouts, and that its humidity should be at the point of 

 saturation, or nearly so. We have found that the same plants 

 which refused to grow when placed upon the stage of a hot- 

 house, the air of which possessed the necessary conditions of 

 heat and vapour, flourished with all their native luxuriance, 

 if the pots, in which they were planted, were suspended freely 

 by wires from the roof; a difference which, no doubt, de- 

 pended essentially upon drainage ; and we have seen that 

 moss alone would, under these circumstances, maintain in 

 perfect health plants which the most carefully managed soil 

 appeared to kill, if the humidity of the air and the drainage 

 were unattended to. 



" Having originally taken great interest in this enquiry, I 

 have for some vears been collecting* information relating to it, 

 and I find that if we had had, in the beginning, the same 

 knowledge of the native habits of orchideous epiphytes that 

 we now possess, those conclusions, that are now the result of 

 many years' careful and expensive enquiry, would have been 

 obvious inferences prior to any experiments whatever having 

 been instituted. The facts that I have collected are the 

 following : — 



" Orchideous epiphytes grow naturally upon trees, in the 

 recesses of tropical forests : they establish themselves in the 

 forks of branches, and vegetate amidst masses of decayed 



