Evening primrose, also known as hibiscus, is an annual to perennial herb. Its main root is about 1cm in diameter, and its stem is 20-50cm long. Its basal leaves are grayish green, narrowly oblanceolate to oval, its apex is sharp, and its base is gradually narrow or abruptly narrow to petiole.
The flower bud is conical lanceolate or narrow ovate, curved and extended upward before opening, sepals are green or yellow green, the edge is red when opening, the flowers are yellow, and the flowering period is from May to August.
It is native to the Atlantic coast of the United States and the coast of the Gulf of Mexico. It is cultivated and wild in Peru, Chile, Australia, Britain, Spain, Israel, Iraq, Egypt, South Africa, etc.
The main root is very thick. The stem is about 70-150 cm high and 6-20 mm thick. It is often densely covered with pubescence and sparsely extended long hair (trichome red blister).
The basal leaves are rosette like, oblanceolate, sharp or slightly blunt at the apex, with light wavy serrations at the edge, white or red, dark green or bright green at the upper part, yellow flowers, rhombic seeds, brown, angular, with irregular pits on each surface, about half of them are sterile, and the flowering period is from May to October.
The yellow flower and evening primrose herb originated from a hybrid cultivated or wild in Europe. It was spread from England to various countries for horticultural cultivation in 1860.
Erect to extroverted annual or perennial herbs with main roots, stems 10-50 cm long, often branched, pubescence, sometimes mixed with pubescence, often mixed with glandular hairs on the upper part of stems.
It originated from the eastern to the central part of the United States, and later was cultivated in Europe, East Asia, Australia and South Africa, and quickly escaped from the wild.
Perennial herb with thick main root and tufted stem, about 30-50 cm, petiole light purple red, filament white to light purple red, 5-7 mm long, anther pink to yellow.
Originated from the south of Texas to Mexico, it is also found in the southwest of the United States, Central America and the warm temperate zone of South America.
