196 THE SCHOOL GARDEN BOOK 



members of the iris group, the individual parts are so large 

 that they are readily seen and comprehended by any one. At 

 the base of the blossom there are two clasping parts which form 

 the spathe. They cover the undeveloped buds and generally 

 enclose the ovary or fruit pod at the base of the flower. This 

 ovary, which is easily seen by pulling one of the valves of the 

 spathe to one side, is more or less longitudinally ribbed and 

 furrowed. 



Arising from the top of the ovary, as we see it from the 

 outside, is the perianth tube, which is a little less than an 

 inch long, and gives rise at its upper end to the showy parts 

 of the flower. These consist of three large sepals, having 

 enlarged outer ends curving downward. Each of these 

 downward parts is called a "fall." Arising from between 

 the bases of these sepals are very slender petals which curve 

 upward and inward, rather than outward and downward. 

 These are commonly called the "standards." 



The combination of the downward-curving falls and the 

 upward-curving standards offers opportunity for an infinite 

 variation in the display of colors, and in the scores of varieties 

 of the German Iris some of the most beautiful and delicate 

 colors conceivable are displayed on these surfaces. The 

 space above the sepals and between the petals is occupied by 

 a curious modification of the central pistil of the flower, 

 which covers and protects the stamens, and which projects 

 upward at the end to form what the florists call the "crest." 

 Just below the crest is a stigmatic surface upon which pollen 

 must be left if the ovules in the seed pod are to develop into 

 seeds. 



In the conditions of nature, this whole curious device of 

 the structure of the iris serves to bring about the cross- 



