'loco weed' definitions:

Definition of 'loco weed'

From: GCIDE
  • Loco \Lo"co\, n. [Sp. loco insane.]
  • 1. (Bot.) A plant (Astragalus Hornii) growing in the Southwestern United States, which is said to poison horses and cattle, first making them insane. The name is also given vaguely to several other species of the same genus. Called also loco weed. [1913 Webster]
  • 2. (Bot.) Any one of various leguminous plants or weeds besides Astragalus, whose herbage is poisonous to cattle, as Spiesia Lambertii, syn. {Oxytropis Lambertii}. [Webster 1913 Suppl.]