Stems: erect, stout, wand-like. Leaves: lanceolate, acute, narrowed and sessile at the base, repand-denticulate. Flowers: spicate, terminal, leafy-bracted; calyx-tube slender, the lobes linear, reflexed.
The Evening Primrose, whose bright yellow blossoms open in the twilight, somewhat resembles the Yellow Willow-herb, whose paler flowers bloom at the bidding of the sunshine. Seen in the daytime, the Evening Primrose appears faded and uninteresting; but viewed at night, its fragrant flowers are exceedingly attractive. The plant grows to an average height of three feet, and has alternate lance-shaped leaves and erect buds. No sooner has the sun set than the buds begin to expand, the closely closed calyx suddenly bursting open with a loud pop, and then one by one the petals slowly unfold, until the whole sulphur-coloured flower is wide-blown and sends forth its sweet fragrance to scent the evening air.
"A tuft of evening primroses O'er which the mind might hover till it dozes, But that it's ever startled by the leap Of buds into ripe flowers."
A single summer night suffices to consume the vitality and beauty of this flower, which at evening is fresh and fair and newly blown, and by noon looks faded and most dejected. It is strange how very fragrant and lovely are many of these "flowers that blow when the heat of the day is o'er." such, for instance, as the Night-blooming Jessamine, the Night-blooming Cerens, and the Night-blooming Cactus. The yellow petals of the Evening Primrose shine so luminously in the dusk that they easily attract the crepuscular moths, which fertilize the plants by carrying the abundant sticky pollen from one flower to another. The number four is conspicuous in this flower, which has four petals, a four-parted calyx, eight stamens, a four-celled ovary, and a four-cleft stigma. When the corolla fades, after its single night of revelry, it soon shrivels and drops off, and then the oblong capsule containing the seeds quickly matures