FLOWERS, THEIR STRUCTURE AND KINDS 14$ 



The Evening Primrose. 

 ((Enothera biennis = Onagra biennis.) 



234. The flowers of -the evening primrose are formed in a 

 rather loose spike, which continues to grow at the end, producing 

 new flowers in the axils of the bracts, while the seed is ripening in 

 the lower older fruit pods. In vigorous plants flower spikes are 

 also formed on the branches in the axils of the upper leaves. 



235. The calyx forms a long tube, the lower part of which is 

 joined to (adnate) the outside of the ovary. This tube is pro- 

 longed far above the apex of the ovary and is about twice the 

 length of the young ovary. The 



free part of the tube is easily 

 distinguished from the part adnate 

 with the ovary by its light green 

 color. The calyx lobes are four 

 in number, long, narrowly acu- 

 minate, and in the flower bud 

 the edges fit closely, giving the 

 bud an elongate, four-angled, 

 pointed form. These calyx lobes 

 are the free parts of the sepals, the 

 edges of which are united below to 

 form the tube. As the flower opens 

 the calyx lobes part, and become 

 inverted, hanging downward from 

 the apex of the tube. 



236. The corolla is bright yel- 

 low and consists of four petals which the long style> 



are inserted on the edge of the calyx tube. Each petal is broadly 

 wedge-shaped and notched in the free end, or rather it is heart- 

 shaped. The petals are convolute in the bud, as shown in fig. 108, 

 where they are just unfolding. 



237. The stamens are eight in number, seated also on the 

 edge of the calyx tube and partly on the base of the petals since 



Fig. 106. 



Flower of evening primrose (OZ. bien- 

 nis) with corolla tube split open to show 



