272 



Plant-Breeding 



although it is sometimes in the form of a more or less 

 glutinous or adhesive mass, as in the milk-weeds and 

 orchids. The irritating dust which falls from the corn 

 tassels at the later cultivatings is the pollen. 



The pistil, or so-called female organ, is shown at OP, 



Fig. 81. The enlarged 

 portion at is the ovary, 

 which develops into the 

 seed-pod. The stigma, or 

 the enlarged and rough- 

 ened part which receives 

 the pollen, is at P. Be- 

 tween these two parts is 

 the slender style, a part 

 that is absent in many 

 flowers. 



The stamens and pistils 

 are known as the essen- 

 tial organs of the flower, 

 for, whilst the calyx and 

 corolla may be entirely 

 absent, either one or both 

 of these organs is present ; 

 and these are the parts 

 that are directly concerned in the reproduction of the species. 

 Like the floral envelopes, these essential organs are often 

 modified, so much so that botanists are sometimes perplexed 

 to distinguish them from each other or from modified forms 

 of the petals or sepals. The particular features of these 

 organs which the plant-breeder must be able to distin- 

 guish are the anther and the stigma ; for the anther bears 



FIG. 82. Flower of greenhouse 

 cypripedium. 



