Flowers axillary or forming spikes at the top of stems; Calyx angular, lobes subulate; Corolla is usually yellow, red or white, and capsule is ovoid and surrounded by persistent calyx. Flowers bloom in autumn. Witchweed is an annual semi-parasitic herb of the genus Witchweed belonging to Scrophulariaceae, which is distributed in Yunnan, Guizhou, Guangxi, Guangdong, Hunan, Jiangxi, Fujian and Taiwan Province provinces in China. Tropical Asia and tropical Africa are widely distributed. It grows in low-altitude crops, barren hills and grasslands, fields, valleys and cultivated land.
The golden stem of one leg is solitary and has few branches. The leaves are narrow, only the base is narrowly lanceolate, and the rest are strip-shaped, 0.5-2 cm long and sometimes scaly. Flowers axillary or forming spikes at the top of stems; Calyx has 10 edge, 4-8 mm long, 5-lobed in the middle, and lobes subulate; Corolla is usually yellow, less red or white, with a length of 1- 1.5 cm, the top of corolla tube is sharply curved, and the upper lip is short and 2-cleft. Capsule ovoid, surrounded by persistent calyx.
Polygonum multiflorum Thunb. is induced to take root for about 20 days, and the regenerated plants of Polygonum multiflorum Thunb. are transplanted, with the root length of 0.5-2 cm and the seedling height of more than 3 cm. First, the bottle cap of the culture was opened, and the seedlings were tempered indoors for 3-7 days, then the root culture medium was washed with tap water, and then soaked in 0. 1% carbendazim solution for 10 min. Finally, the seedlings were planted in the sterilized peat soil and garden soil mixed matrix, and the environmental humidity was maintained.