Narrow-leaved weeds, arranged in sets of three and triangular stem are called?

Based on the morphology of the plant, the weeds are also classified into three categories.
This is the most widely used classification by the weed scientists.
Types of Weeds
Grasses (Family: Poaceae):
Characterized by long, narrow, spiny leaves.
Examples:
Echinocloa colonum
Cynodon dactylon
Sedges (Family: Cyperaceae):
Leaves mostly arise from the base; may have modified stems with or without tubers.
Examples:
Cyperus rotundus
Fimbrystylis miliaceae
Broad-Leaved Weeds:
This major group includes all dicotyledon weeds not covered by the previous categories.
Examples:
Flavaria australacica
Digera arvensis
Tridax procumbens