DEVELOPMENT OF PLANTS 



43i 



323). This latter plant flourishes in rather dry soils, forming 

 large colonies by its underground stems and gaining in con- 

 spicuousness through its terminal racemes of large deep purple 

 flowers. The parts of the flower are in fours. The receptacle 

 adheres to the ovary and bears the linear segments of the calyx 

 alternating with the round spreading petals. At the time of the 

 opening of the flower the eight anthers are shedding their spores 

 and in line with the nectaries, while the four-lobed stigma is 

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



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 sepals cohere, forming a tube, 

 t, that bears at its summit the petals, />, and stamens ; c, lobes of the calyx. 

 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 discharging 

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



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 

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



