1, Gramineae weeds characteristics: round or slightly flat stems, obvious differences between nodes, hollow nodes, central sheath, often tongue-shaped. Embryo has 1 cotyledon, narrow and long leaves, parallel veins, sessile leaves and fibrous roots, such as barnyard grass, crabgrass, cattail, dried grass, etc.

2. The main morphological characteristics of broad-leaved weeds are round, heart-shaped or rhombic leaves, reticulate veins and round or quadrangular stems. Such as Alternanthera philoxeroides, annual awnings, dripping vegetables, etc.