Detailed Explanation of the Botanical Characteristics and Growth Habits of Asarum heterotropoides
Asarum is a perennial herbaceous medicinal plant of the genus Asarum in the family Aristolochiaceae. Wild species include Asarum heterotropoides (Aristolochiaceae het-arotropoides Fr.) distributed in Northeast China and Asarum sieboldii (A. sieboldii Miq.) distributed in Shaanxi. The whole plant of Asarum is used as medicine; it has the effects of dispelling wind and dispersing cold, warming the lungs and eliminating phlegm, and opening the orifices and dredging the collaterals. It can treat wind-cold headache, rheumatic arthralgia, phlegm-fluid cough and asthma, toothache, and sinusitis. The whole plant of Asarum has a special pungent aroma. In addition to medicinal use, it is also a raw material for the fragrance industry and a good insect repellent.
Asarum heterotropoides is a perennial herb. It grows 2-3 leaves from the rhizome. The petioles are 5-20 cm long. The leaf blades are heart-shaped or round-kidney-shaped, 4-10 cm long and 6-13 cm wide, with entire margins, green on the surface and grayish green on the underside. Underground there is a horizontally creeping rhizome that produces many slender roots. The flowers are solitary in the leaf axils, with slender short pedicels, shaped like a tobacco pipe bowl. The corolla is purplish brown, urn-shaped, with three lobes at the apex; the lobes are ovate and recurved outward. The fruit is hemispherical and contains numerous seeds, with a 1000-seed weight of 4.89 g.
Growth Habits of Asarum
Asarum mostly grows under mountain forests or among shrubs and in shaded, damp grassy areas in the mountains. It prefers well-drained, humus-rich, and relatively moist soil. Both seedlings and mature plants can overwinter in the field. Asarum is a shallow-rooted, shade-loving plant. In early spring, it emerges earlier than other crops. During its growth stage it avoids direct strong light, and field cultivation requires artificial shading. It can grow normally under conditions of "dappled sunlight" or "scattered light," and grows slowly in high-temperature seasons. If the temperature exceeds 35°C, the leaves turn yellow and wither, and the plants often die back early. It blooms in May, and the seeds mature in June-July.