ITS CHARACTERISTICS. 79 



Its ovate, rough, irregularly-dentated, and petiolated leaves 

 would not give it a sufficiently marked character, had it no 

 other features peculiar to itself. But observe the yellowish- 

 green glomerules, arranged, like millet, on a long frail spike. 

 (Fig. 1 8, a.) They exhale, as your nose will inform you, a 

 peculiar aroma, like that of spiced bread: no other plant 

 but our Dog Mercury is gifted with this odour. Now, bring 

 your magnifying-glass to bear upon it ; with the point of a 

 knife or a feather open one of the grains which form the 

 glomerules of the spike ; out of it will leap, as if impelled by 

 an invisible spring, a large number of stamens, easily dis- 

 tinguished by their elastic thread-like anthers, covered with 

 tiny yellow beads. Each greenish grain is a flower; the calyx, 

 which also serves as the corolla, is represented by three little 

 petals, forming the external envelope of the little flower. 

 (Fig. 1 8, b.) But something essential is still wanting ; in the 

 centre of the stamens you do not find any pistil. Why is 



FIG. 18. 



so important an organ wanting ? Because our little rounded 

 flowers, with their spice-bread odour, have but one sex, are 

 unisexual ; they are male flowers, since they are furnished 



