EXTRACTS. 239 



culty ii> theii- cultivation; and .. was therefore resolved that au attempt should 

 be made to overcome this difficulty, in the Chiswick Garden. Similar at- 

 tempts, before or about the same time, were made in the stoves of Messrs. LoD- 

 DiGEs's of Hackney, Messrs. Richard and Arnold Harrison of Liverpool, 

 Mr. Cattle Y of liarnef, and others; so that the total number of species of 

 this family of plants found in Britain at the time Dr. Lindley's paper was 

 read, was not less than 200 ; bat in Dr. Lindley's recent publication, up- 

 wards of 1000 species are described; while the catalogue of the Paris Garden, 

 made up to 1829, enumerates only nineteen. 



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 conditions that are requisite to ensure their successful cultivation, and 

 that soil itself is of little importance to them. We have used common gardeu 

 earth, lime rubbish, gravel, decayed vegetable matter, and moss, and all with 

 equal success, provided the drainage was effectual; and we have found all 

 these equally useless when the drainage was not atlended to ; a circumstance 

 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 temperature and atmospheric humidity were care- 

 fully regulated. To speak very accurately on these points, I should say, that 

 the mean temperature of the day ought to be 97" 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 

 hothouse, the air of which possessed the necessary conditions of heat and 

 vapour, flourished with all their native luxuriance, if the pots, iu which they 

 were planted, were suspended freely by wires from the roof; a difference which, 

 no doubt, depended 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 inquiry, I have for some 

 years been collecting information relating to it, and I lind 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 vegetable and animal matter. In consequence of 

 their position, there cannot possibly be any accumulation of moisture about 

 the roots, 'i'hey will also grow equally well upon rocks, and stones in similar 

 situations. Mr. W. Harrison, of Rio Janeiro, is mentioned by one of the 

 Society's collectors, who visited him, to cultivate, with the most perfect success, 

 above seventy species upon a wall iu his garden at Uoto Fozo. 



"We see some of them germinate and grow most luxuriantly in damp 

 places, in the stove, upon the sides of the garden pots, and among gravel , and 

 Dr. W'xi.ucn found them in all cases growing e<iually well upon trees and 

 stones, provided the latter had a certain quantity of mould and moss adhering 

 to them. 



"In the Botanic Garden iit Calcutta they arc cultivated with success in 

 raised beds of solid brickwork, so contrived as to secure the most perfect 

 drainage; the soil being rich vegetable matter, mixed with at least two thirds 

 small i»ebbles, and covered with a dense layer of moss. 



" Shade seems esse iitial to them: tluir natural situation being In deep forests, 

 or among the branches of growing tree.s. In Brazil they exclusively occupy 

 damp woods and rich valleys, among vegcl.\tion of the most luxuriant descrip- 

 tion, by which thiy are embowered. Iu Nipal I learu from Dr. Wallicii 



