ONAGRACEAE (EVENING PRIMROSE FAMILY) 295 
parted white stigma; ovary below the calyx-tube and four-celled. 
The plant is good bee pasture, generous of both pollen and nectar. 
Capsules two inches or more long, obscurely four-sided, reddish 
brown, velvety-hairy when young, many-seeded, opening at the 
summit. Seeds small and brown, tufted with white hair finer 
than thistle-down, by which they are widely wind-sown. (Fig. 205.) 
Means of control : 
Close cutting or hand-pulling before the development of seeds ; 
destruction of the perennial roots by cultivation of the ground. 
COMMON EVENING PRIMROSE 
Cnothéra biénnis, L. 
(Onagra biénnis, Scop.) 
Other English names: Field Primrose, Tree Primrose, Fever Plant, 
Night Willow-herb. 
Native. Biennial. Propagates by seeds. 
Time of bloom: June to September. 
Seed-time: August to November. 
Range: Labrador to Florida, westward to the Rocky Mountains. 
Habitat: Dry soil; fields, meadows, roadsides, waste places. 
The long, stout taproot of this plant is used in Germany as a 
table vegetable, like parsnips, and its young crown leaves are 
blanched and used for salad. It is also medicinally valuable. 
Collectors receive about five cents a pound for the plants pulled 
entire in mid-flowering time and dried in the shade. 
Stem two to six or more feet tall, rather stout, usually simple, 
more or less hairy. Root leaves lance-shaped, three to six inches 
long, the surface dark green, rough-hairy, slightly toothed, tapering 
to a petiole; stem leaves much smaller, alternate and sessile. 
Flowers in terminal leafy-bracted spikes, sessile, the calyx-tube 
sometimes two inches long, its four lobes reflexed and falling 
away; stamens eight, inserted on the top of the calyx-tube; 
style with deeply four-cleft stigma; ovary below the long calyx- 
tube, itself much elongated and four-celled ;_ the four broad, sulfur- 
yellow petals are rolled in the bud, and at the falling of twilight 
their unfolding is so swiftly accomplished that one may “see her 
