Japanese hedge parsley; erect hedge parsley
A common annual plant (Torilis japonica) in the carrot family, native to East Asia and naturalized elsewhere. The name literally means 'bush louse' because the small burrs cling to clothing like lice.
A lot of Japanese hedge parsley is growing along the roadside.
The seeds of Japanese hedge parsley easily stick to clothing.
Compound of 藪 (yabu, 'thicket, bush') and 虱 (shirami, 'louse'), referring to the plant's clinging burrs. The exact historical derivation is uncertain, but the name is conventionally associated with this imagery.