172 



THE REPRODUCTIVE ORGANS 



In the Geranium the calyx has five sepals joined by 

 their edges to form a deep tube. A united calyx is said to 

 be gamosepalous (Gr. gamos = union). The five petals 

 are free ; there are ten stamens, five outer and five inner. 

 At the bases of the five outer ones are nectaries. It is 

 interesting to watch the movements of the stamens in the 

 Field Geranium. When the flower opens, the stamens lie 

 on the petals ; they then raise themselves parallel to the 

 pistil, shed their pollen, and return first the outer set, then 

 the inner to their former position. The pistil consists 



Fig. 117. 1, Flower of 

 Garden Geranium ; 2, trans- 

 verse section of pedicel and 

 nectary ; n, nectary ; p, pedicel 

 of flower. 



Fig. 118. Flower of Gar- 

 den Nasturtium. n, honey- 

 secreting spur ; p, pedicel. 



of five superior, united carpels. When the pollen is shed, 

 the stigmas ripen and spread out as five lobes to receive 

 pollen from another plant. Stamens which ripen before the 

 pistil are said to be proterandrous. 



Compare with this the Garden Geranium (Pelargonium) 

 (Fig. 117). In this, do the stamens of the stigmas ripen 

 first ? In these flowers cross-pollination is secured by the 

 stamens and the pistil, which, though existing in the same 

 flower, ripen at different times. Look for the long tubular 

 nectary which adheres throughout its whole length to the 

 flower-stalk. The presence of the nectary in the Pelar- 



