xxii INTRODUCTION 



and until the year 1859 the absolutely non-committal 

 and inexplicable flower; the blossom which had waited 

 through the ages for Darwin, its chosen interpreter, ere 

 she yielded her secret to humanity!" 



To understand readily the metamorphosed structure of 

 the orchids it will be helpful to recall the parts of a simple 

 regular flower as they appear in their concentric circles, 

 represented in Plate I., Fig. i. Contrast these with the 

 elaborately varied petals of the Yellow Fringed Orchis as 

 seen in Plate I., Figs. 7 and 8. The orchid family is closely 

 related to the lily and the iris family, and has its parts in 

 threes; but the three parts of each circle are by no means 

 symmetrical. Of the outer circle two sepals are alike, but 

 the third is enlarged, making a hood over the petals. In the 

 next circle two j>etals are alike, but the third is much elong- 

 ated, fringed and beautifully marked. This fringed petal 

 is called the lip. It may be pouched as in the Lady's- 

 Slipper, or covered with bristles, or pinched, or toothed, or 

 brilliantly coloured, so that it can in some way attract insects 

 to visit it. 



This lip, properly speaking, is the upper petal and would 

 stand up in the air like a banner, were it not that the ovary, 

 which in all the lilies and irises is perfectly straight, is, in the 

 orchid family, with but few exceptions, twisted completely 

 around. This causes the lip to hang, and permits it to 

 become larger and more elaborately modified than the other 

 petals or the sepals. 



In the particular orchid in the illustration, Plate I., Figs. 7 



