ORCHIDS. 295 



by signs, to give me a number of roots, but they did not grow well 

 in my garden. 



The more splendid forms of orchids are not terrestrial, but epiphytic, 



growing on trees and rocks in their native country. The roots cling 



closely to the trees or rocks, and for that reason are called air plants ; 



but I suspect that they draw much nourishment, and especially earthy 



salts, from the plants on which they grow. During their period of growth 



a nearly saturated atmosphere is absolutely necessary; and at all times 



of the year it is desirable that the air should be very humid. Probably 



more orchids are killed by excess of heat, and a daily variation of the 



dryness of the air, than from any other cause. They will not bear a 



dry atmosphere, and heat combined with dryness causes certain death. 



I do not pretend to grow exotic orchids, but I never refuse a spare bulb 



from a friend. They grow with me like weeds, and so by the gifts 



of many kind friends I have now more plants growing, in good health 



than existed in the country when I was born. The secret of my 



success is to supply water by giving moisture to the air, and not to soak 



the roots of the . plants. The greater part of my orchids are grown in 



the fernery, and the highest temperature which any of my plants get is 



that which is necessary for the growth of cucumbers. Some of them, 



as the Cypripediums and Dendrobium npbil.e, are grown in winter at a 



temperature very little above freezing, ajid indeed occasionally they 



may get a little frost, which^ however^ is, to, be avoided rather than 



to be commended. All the epiphytic orchids. sh,un the direct rays o,f 



the sun, but rejoice in. ligh,t Thej: never do well, in, a large house» 



probably because the hygrometric ^ate constantly varies. The part of 



my fernery in which the orchicfe. grow has some light admitted from 



the south ; but rows of trees are planted before the glass, effectively 



to intercept the direct rays of the sun in summer, though some of 



the rays in winter are beneficially admitted. 



Most orchids do best if potted in broken pieces of pots inter- 

 mingled with the. fibre of peat and sphagnum moss. By this, 

 mode of growth the roots are always freely exposed to aiir and 

 moisture. 



