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mad-dog skullcap

[mad-dawg, -dog]
noun Botany.
  1. a North American skullcap, Scutellaria lateriflora, having underground stems and one-sided clusters of blue to white flowers.

Origin of mad-dog skullcap

An Americanism dating back to 1815–25; so called because it was formerly used as an antispasmodic
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018