EVENING PRIMROSE FAMILY 



ONAGRACEAE 



COMMON EVENING PRIMROSE 



Oenothera biennis L. 



The Common Evening Primrose grows abundantly in open 

 places, usually in rather dry soil, from Labrador to Florida and 

 west to Minnesota and Texas. This is a biennial that produces 



the first year only a rosette of 

 leaves and a strong root. 

 The fleshy root is said to have 

 been used as a table vegetable 

 long before potatoes were cul- 

 tivated so universally. The 

 rosette of leaves remains green 

 all winter and in the spring 

 there is produced an upright, 

 leafy, more or less branched 

 shoot that grows i-6 feet high 

 and bears the flowers and fruits. 



In Illinois this Evening 

 Primrose begins blooming in 

 June and continues until stop- 

 ped by the frosts of October. 

 The beautiful and fragrant 

 flowers open at sundown and 

 are interesting to watch. They 

 close the following day and 

 so are pollinated by night- 

 flying moths. The 4 bright 

 yellow petals and 8 stamens 

 are inserted on the long and 

 narrow calyx tube, which is terminated by 4 narrow reflexed 

 lobes. The style is slender and the stigma 4-lobed. The mature 

 capsules are three-quarters to i }4 inches long and are covered 

 with short hairs. They contain as many as 40 seeds each, and a 

 mature plant once examined was thus found to produce 500,000 

 seeds. 



The Northern Evening Primrose, Oenothera niuricata L,, is 

 commonly associated in this state with the above species, and is 

 usually mistaken for it. However, it grows not more than 3 feet 

 high instead of having the 6-foot range of the Common Evening 

 Primrose, its leaves are narrower and more nearly entire, and above 

 all, the hairs on its stems rise from reddish glands. 



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