464 



THE MYRTALES 



mouth the Hnear segments of the calyx alternating with the 

 round spreading petals and the stamens. At the time of the 

 opening of the flower the eight anthers are shedding their spores 

 and are in line with the nectaries, while the lobed stigma is 

 closed and bent backward (Fig. 323, C, s). A day later the 

 stigmas assume the position shown in the lower flowers, the lobes 

 curving backward so as to lie in the pathway leading to the 

 nectaries (Fig. 323, C, 0). It is evident that these positions 



Fig. 323. Higher forms of the Myrtales, flowers epigynous: A, flower 

 of Oenothera — 0, ovary. B, enlarged sectional view of flower, showing the 

 receptacle enveloping the ovules. The receptacle grows above the ovary, 

 forming a tube, f, that bears at its summit the lobes of the calyx, c, the petals, 

 p, and stamens. C, inflorescence of the great willow herb (Chamaenerion) 

 — s, closed stigma in young flowers; 0, opened stigmas in older flowers; a, 

 stigma touching anthers in withered flowers. D, capsule opening and dis- ^ 

 charging the seeds. E, a seed enlarged. — C after Kerner, 



must necessitate a crossing if the flowers receive the proper vis- 

 itors. If, for any reason, crossing should fail autogamy results, 

 owing to the continued curvature of the stigmas, which are finally 

 brought into contact with the anthers, in which work the positions 

 of the flowers and stamens cooperate, as shown in the lowest 



