FLOWERS, THEIR STRUCTURE AND KINDS 



161 



four short, nearly cylindrical lobes at the apex of the style. In 



the flower bud these are erect, approximate, and project a little 



above the convolute petals. Here the 



inner faces of the anthers are pressed 



closely against the lower half of the 



outer face of the stigmas and deposit the 



pollen on them as described above. 



The four parts of the ovary and the 

 four lobes of the stigma indicate that 

 the pistil is made up of four parts, or 

 carpels, which have become united into 

 one compound pistil. All of the parts 

 of the flower, therefore, of the evening 

 primrose are in fours. 



254:. Lamark's evening primrose. 

 One species of the evening primrose, 

 (Enothera lamarkiana (Lamark's even- 

 ing primrose), has become celebrated 

 through the experiments of the Dutch 

 botanist, DeVries, for the sudden varia- 

 tions which appear in plants grown from 

 the seed, giving rise to distinct forms. 

 These forms are regarded as elementary 

 species, and as indicating one method of 

 the evolution of new species. (See 

 paragraph 662.) 



Fig. 118. 



Photomicrograph of pollen 

 of evening primrose, showing 

 threads which hold the grains 

 in loose masses. 



Butter and Eggs. 

 (Linaria vulgaris= Linaria linaria.) 



255. This plant occurs by roadsides and in waste places. It 

 is from one to nearly three feet high (3-9 decimeters), branched, 

 with linear leaves. The leaves are mostly alternate, but are often 

 grouped on the stem, two, three, or four arising close together 

 on the stem and almost opposite or verticillate. 

 ii 



