INTRODUCTION xix 



orchids are obliged to take heed as to what they shall eat 

 and drink as much as to what they shall wear. But like 

 the aristocracy of society who are supposed to know nothing 

 of their kitchens and plumbing, the orchids are supposed to 

 live wholly on air, and never dig into the earth for their food 

 supply. This is true of more than half of the three thousand 

 species that inhabit the earth, true of some of those marvel- 

 lous fantasies of form and colour that perch like brightly 

 plumaged birds on the high trees of tropical forests. Where 

 are the alchemists who transform the air and sunshine into 

 silk-textured petals dyed with the rarest colours .? In the 

 green leaves we find that the chlorophyl grains, those minute 

 round green pigment cells, that colour the leaves, are the 

 analytical chemists, that, in the presence of sunlight split 

 the air and water into their elements and then mix new food 

 compounds for the plants' special needs, much as a skilful 

 cook might make bread or cake or doughnuts by using 

 the same materials in different proportions. 



But how can the orchids, living so far from the ground, 

 obtain their water .? It might appear that they drew it 

 through the roots that they fasten like talons into the 

 branches of the trees, but that would make them parasites. 

 No, the roots get their water from the moisture in the air, 

 while a few are set aside as grappling hooks to fasten the 

 orchid securely in place. 



When a young orchid sprouts from the seed that has lodged 

 in a congenial tree top, it sends out a root tip that flattens 

 itself against the bark, sometimes laying itself along like 



