Red-maple hybrids should be considered toxic until proven otherwise.

This is the third in a series of articles on toxic plants that are likely to poison horses in North America. This installment covers myotoxic plants, those that damage muscle and the cardiovascular system.

This is the second in a series of articles introducing the toxic plants most likely to poison horses in North America.

Because antidotes are rare, plant-induced diseases in horses can be irreversible and sometimes lethal.