Setaria glauca, Yellow Foxtail, yellow bristlegrass, pigeon grass
Description: summer annual
Place of origin: Europe
Urban habitat: roadsides, vacant lots, along railroad tracks, cultivated landscapes, gravel, spreads rapidly in disturbed areas
Ecological function: disturbance-adapted colonizer of bare ground, food for wildlife
History: originally introduced from Europe, Setaria pumila is now found throughout the US and Canada where it is considered a noxious weed in many places; in agricultural settings, yellow foxtail can be toxic to nearby crops through allelopathy, a process that enables it to reduce competition by stunting nearby plants via chemicals produced by its roots that travel through the soil.