Wild Flowers East of the Rockies 225 



EVENING PRIMROSE (Oenothera biennis) is an 



exceedingly common biennial plant, so persistent and 

 so profuse in its growth, that it is often regarded as 

 an obnoxious weed. Its common name was given it 

 because of its nocturnal habits, the flowers spread- 

 ing wide open at dusk and partly or wholly closing 

 the next morning. 



The stem is soft-hairy, quite stout and often very 

 tall, ranging from 1 to 6 feet in height. It is usually 

 simple, but sometimes branches, especially in the 

 Fall. Both the stem and the leaves are rather 

 coarse in texture; the latter are lanceolate, stemless 

 and rough-edged or very slightly toothed. The flow- 

 ers are seated in the angles of the upper leaves; they 

 appear to be on stems, for the calyxtube is very 

 long and slender, with the four lobes, or sepals, re- 

 flexed. The four, pale, lemon-yellow petals are large 

 and rounded, the flower spreading slightly less than 

 two inches; the eight stamens have golden-yellow 

 anthers. 



The lower buds open first, only a few at a 

 time, so that usually we may find seed-pods seat- 

 ed among the leaves just below the flowers and un- 

 developed buds and leaves above. It is fertilized 

 sometimes by bees in the daytime, but chiefly by 

 night-flying moths. A large variety (grandiflora) is 

 often cultivated and sometimes escapes. It is an 

 European species with flowers measuring 3 or 4 

 inches across. The Primrose blooms in fields and 

 roadsides, everywhere, from July to September. 



SUN DROPS (Oenothera fructicosa) a somewhat 

 similar, diurnal species, with a branched stem grows 

 1 to 3 feet high. The pale yellow flowers measure 

 from y 2 to 1 inch across; they are in loose terminal 

 clusters or from the angles of the upper leaves. The 

 leaves are linear-lanceolate, slightly toothed. Com- 

 mon from Me. to Minn, and southwards. 



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