-By John Lindley, Esq. 



49 



order almost disappears. On the west coast of South America, as 

 high as Lower Peru, they are unknown ; a circumstance which will 

 not be surprising, when we consider the effect of the currents set- 

 ting round Cape Horn, which bring the mean temperature of even 

 Lower Peru itself down to 60° at night, and how arid the whole of 

 that region is with the exception of a few vallies. 



From this I think it may be safely deduced as a certain fact, that 

 the most favourable conditions for the growth of Orchideous Epi- 

 phytes, are as I have before stated, a well drained soil, a shady situa- 

 tion, a saturated atmosphere, the mean temperature of which is not 

 less than from 79° to 80°, and a complete protection from dry parch- 

 ing winds. Such appears to be the climate to which they are na- 

 turally subjected, in most cases ; with the exception of the species 

 found in the Mexican Andes. Two species are indeed found in 

 Japan, the mean temperature of which is no doubt much lower 

 than what I have stated, and it appears from Mr. Brown's re- 

 marks that in New Holland they are less numerous within the 

 tropics, than in the parallels of 33° to 35° S. L. the mean temperature 

 of which is probably not very different from that of Port Jackson, 

 viz. 66° 6'. 



If then we reflect upon the natural habits of Orchideous Epi- 

 phytes, and upon the little similarity that often prevails between the 

 atmosphere of hothouses and that in which, alone, it has been seen 

 that they can exist, we shall cease to wonder at any failure, that 

 may have attended their cultivation. No accuracy was formerly 

 observed in the proportion of vapour and temperature in the at- 

 mosphere of a stove ; a circumstance which must have been fatal 

 to many plants besides those now under consideration. Even at 

 the present day the air of many of the hothouses that I see would, 

 I am persuaded, be found to indicate 6° or 7° of dryness, a condi- 

 tion to which such plants as these are never subjected by nature ; 

 in those districts of the East and West Indies where such a climate 



VOL. r. 2nd series. H 



Mo. Bot Garden, 



