1, morphological characteristics of Amaranthus dentatus: plant height 10-30cm, the whole plant is hairless. The stems are recumbent and ascending, some branches of the stems are purple-green or red, smooth, with alternate leaves, petioles, ovate or rhombic-ovate leaves, blunt and concave apex, broad wedge-shaped base, and the petioles and leaves are the same length. Flowers axillary, spikes or panicles. Perianth 3, membranous. The flowering period is from July to August, and the fruiting period is from August to September.

2. Morphological characteristics of Amaranthus retroflexus: up to 1 meter; Stems stout and erect, light green, rhombic or elliptic-ovate leaves, sharp or concave ends, wedge-shaped base, pilose sides and edges, and dense hairs below.

Petiole light green, pilose. Panicle terminal and axillary, erect, terminal spike longer than lateral; Bracts and bracteoles subulate, white, perianth segments oblong or oblong-obovate, white, utricle oblate, membranous, light green, seeds subglobose, with blunt edges. The flowering period is from July to August, and the fruit period is from August to September.

3. Morphological characteristics of Amaranthus crispus: 40-80 cm high, all hairless; Stems erect, edges and corners inconspicuous, slightly branched, green or purplish. The leaves are ovate, oval-oblong or oval-elliptic, the apex is concave or concave, and a few circles are obtuse, with 1 awn tip.

The base is broadly wedge-shaped or sub-truncated, entire or slightly wavy; The seeds are nearly spherical, about 1 mm in diameter, black or dark brown, with a thin and sharp annular margin. The flowering period is from June to August, and the fruiting period is from August to1October.

Second, the growth environment is different

1 Growing environment: Amaranthus rutaecarpa is native to tropical Africa, and it is widely grown in northeast China, north China, east China, south China, Shaanxi, Yunnan, Xinjiang and other provinces except arid and semi-arid areas where rainfall is scarce.

2. The growing environment of Amaranthus retroflexus: it is born in the countryside, beside agricultural land, on the grass near people's homes, and sometimes on the roof of a tile house. Amaranthus retroflexus has strong adaptability, can grow everywhere, is not shade-tolerant, and does not grow well in dense planting fields or tall crops.

3. Growing environment of Amaranthus crispus: It likes warm plants and has strong photophobia, and grows in weeds or fields near houses. Sufficient light is needed during the growing period. Amaranth is drought-resistant, barren-resistant, acid-resistant and salt-tolerant, but it is also afraid of waterlogging and frost, which consumes a lot of soil fertility and can obtain high yield under the condition of sufficient water and fertilizer.

Third, the distribution range is different

1, amaranth distribution: widely distributed in temperate zone, tropical zone and subtropical zone, and also distributed in Japan, Argentina, Australia, Netherlands and some countries in northern Africa. Strong stress resistance, moisture resistance and alkali resistance, lax requirements on soil and wide adaptability.

2. Distribution range of Amaranthus retroflexus: It is native to tropical America and has been widely spread and naturalized all over the world. China is distributed in Heilongjiang, Jilin, Liaoning, Inner Mongolia, Hebei, Shandong, Shanxi, Henan, Shaanxi, Gansu, Ningxia and Xinjiang.

3. Distribution of Amaranthus crispus: It is produced in Northeast China, North China, Shaanxi, East China, Jiangxi, South China and Yunnan. Native to tropical Africa, it is widely distributed in temperate, subtropical and tropical regions of both hemispheres.

Baidu encyclopedia-amaranth with concave head

Baidu Encyclopedia-Amaranthus retroflexus

Baidu Encyclopedia-Amaranthus rugosa