Pig grass refers to herbs that can be used to feed pigs, not a certain plant. At present, the common pig grass mainly includes Pteris vittata, Mocao, Houttuynia cordata, Auricularia auricula, Astragalus sinicus, sweet potato stems and leaves, etc.

I. Leymus chinensis

Rhizome: a biennial or perennial herb with fibrous roots. Stems ascending, much branched, 50-80 cm long, with glandular hairs on the upper part.

2. Leaves: The leaves are ovoid or broadly elliptic, 2.5-5.5cm long and1-3cm wide, sharp, slightly heart-shaped at the base, and sometimes hairy at the edge. The petiole is 5- 15mm long, and the upper leaves are generally sessile or short-stalked, sparsely pilose.

3. Flowers and fruits: terminal dichotomous cymes. Leaf-shaped bracts with glandular hairs on the edge. Pedicel thin, 1-2cm long, elongated and bent downward after flowering, densely covered with glandular hairs. Sepals ovate-lanceolate or oblong, 4-5 mm long, fruit 7 mm long, blunt tip, narrow membranous margin, glandular pilose outside, and inconspicuous veins. Petals are white, the base is forked, lobes are linear or lanceolate, 3-3.5 mm long and 1 mm wide. Stamens 10, slightly shorter than petals. Ovary oblong, style short, linear. Capsule ovoid, slightly longer than persistent calyx. The seeds are nearly kidney-shaped, about 1mm in diameter, slightly flat, brown and with small warts.

4. Distribution: It is common in rivers and lakes, wet grasslands, ditches, hillsides, roadsides, fields, grasslands and other wet places.

Second, the intestine (ink grass, Eclipta prostrata)

1, rhizome: millet, the stem is erect, inclined or procumbent, up to 60cm long, usually branched from the base and attached with coarse hairs.

2. Leaves: the leaves are oblong-lanceolate or lanceolate, sessile or extremely short, 3- 10cm long and 0.5-2.5cm wide, sharp or tapered, with serrated edges or sometimes only wavy edges, and both sides are thick, hard and rough.

3. Flowers and fruits: the head is about 6-8 mm in diameter, with slender pedicels and about 2-4 cm in length. The involucre is spherical, bell-shaped, green and grasslike, and 5-6 involucres are arranged in two layers, oblong or oblong-lanceolate. The outer layer is slightly shorter than the inner layer, and the back and edges are covered with short white hairs. The peripheral female flowers are 2 layers, tongue-shaped, 2-3mm long, short tongue-shaped, 2-cleft or totally cleft at the top, and most of them are bisexual flowers in the center. Corolla is tubular, white, about 1.5mm long, with 4 teeth at the top. Style branches are obtuse with papillae. Receptacle is convex, with lanceolate or linear stipules, and the stipules are hairy above the middle. Achene is dark brown, 2.8mm long, female achene is triangular, bisexual achene is flat quadrangular, the top is truncated, with 1-3 fine teeth, the base is slightly reduced, the edge is white ribbed, and the surface is small and hairless.

4. Distribution: It is common in rivers, fields or roadsides.

Three, water shield (broken ear root, houttuynia cordata)

1, rhizome: stinky vanilla, 30-60cm high, lower part of stem lying on the ground, upper part erect, glabrous or hairy on nodes, sometimes purplish red.

2. Leaves: thin, papery, oval or wide oval, 4 4- 10/0cm long, 2.5-6cm wide, short and pointed at the top and heart-shaped at the base. Sometimes there is no hair on both sides except the veins, and the back is usually purple. ***5-7 veins, all originated from the midvein (or the innermost 1 pair originated from the midvein about 5mm from the base). If it is 7 veins, the outermost pair of veins are slender and not obvious. Petiole length 1-3.5 cm, glabrous. Stipules are membranous, long 1-2.5cm, blunt at the top, combined with petiole at the lower part to form a sheath, about 8-20mm long, often hairy, swollen at the base, slightly supporting the stem.

3. Flowers and fruits: The inflorescence is about 2 cm long and 5-6 mm wide. The total length of pedicel is 65438 0.5-3cm, and it is hairless. The involucral bracts are oblong or obovate, with a length of 10- 15mm, a width of 5-7mm and a obtuse apex. Stamens are longer than ovaries and filaments are three times as long as anthers. Capsule 2-3 mm long, with persistent style at the top.

4. Distribution: Common in fields, orchards, tea gardens and roadsides.

Fourthly, the bulbous ear curls.

1, rhizome: broomcorn millet, 10-20cm high, solitary or tufted stems, densely villous, with glandular hairs mixed on the upper part.

2. Leaves: The leaves at the lower part of the stem are spoon-shaped, the top is blunt, and the base gradually narrows into a stalk. The upper stem leaves are obovate-elliptic, with a length of 1.5-2.5cm and a width of 5- 10mm, sharp tip, short basal stalk, villous on both sides, ciliate on the edge and obvious midvein.

3. Flowers and fruits: Cymes are clustered or head-shaped, and the inflorescence axis is densely glandular hairy. Bracts herbaceous, ovoid-elliptic, densely pilose. Pedicel slender, long 1-3 mm, densely pilose. ***5 sepals, lanceolate, about 4 mm long, pointed at the top, densely covered with long glandular hairs outside, with narrow membranous edge. ***5 petals, white, linear and rectangular, nearly as long as sepals or slightly longer, 2-lobed at the top and pubescent at the base. Stamens are obviously shorter than calyx. The capsule is cylindrical, 0.5- 1 times longer than the persistent sepals, and the tip is 10 toothed. The seeds are brown, oblate and triangular, with verrucous protrusions.

4. Distribution: Common in vegetable gardens, roadsides or wasteland.

Verb (abbreviation of verb) Chinese milk vetch

1, rhizome: biennial herb, multi-branched, creeping, 10-30cm high, white and fluffy.

2. Leaves: odd pinnate compound leaves, 7- 13 leaflets, 5- 15 cm long. Petiole is shorter than leaf axis. Stipules are free, ovoid, 3-6 mm long, pointed at the top, and more or less United at the base, with cilia. Leaflets are obovate or elliptic, long 10- 15mm, wide (4- 10mm), obtuse or slightly concave at the apex, broadly cuneate at the base, almost hairless at the upper part, with scattered white hairs at the lower part and short stalks.

3. Flowers: The raceme has umbrella-shaped 5- 10 flowers. Axillary peduncle, longer than leaves. Bracts are triangular and ovoid, about 0.5 mm long. Pedicel short, calyx bell-shaped, about 4 mm long, white pilose, calyx teeth lanceolate, about half the length of calyx tube. Corolla is purplish red or orange yellow, flag petal is obovate, long 10- 1 1mm, apex slightly concave, and base gradually narrows into peduncle. The wing flap is shorter than the flag flap and about 8 mm long. The flap is rectangular, with short ears at the base, and the length of the pedicle is about half the length of the flap. The length of keel flap and flag flap is almost equal, and the flap is semi-circular, and the length of flap handle is about one third of that of flap handle. Ovary glabrous or sparsely white pubescent, shortly stipitate.

4. Distribution: It is common in hillsides, streams and damp places.

Six, sweet potato stems and leaves

1. Rhizome: millet, with round, oval or spindle-shaped tuberous roots in the underground part. The stems are horizontal or ascending, occasionally twisted, multi-branched, cylindrical or angular, green or purple in color, fluffy or hairless, and adventitious roots are easily produced in the stem nodes.

2. Leaves: Leaves are usually broadly ovoid, 4- 13cm long and 3- 13cm wide, whole or 3-5(-7) cleft, with broad ovoid, triangular ovoid or linear lanceolate lobes, heart-shaped or nearly truncated at the base, tapering at the top, fluffy or nearly hairless at both sides and thick leaves. Petioles vary in length, 2.5-20 cm long, sparse or glabrous.

3. Distribution: Common in vegetable fields, mostly planted artificially.