Houndstongue (Cynoglossum officinale L.) is a biennial weed infesting pasture, hayfields, and disturbed areas throughout North America. Houndstongue contains pyrrolizidine alkaloids (PAs) that are hepatotoxic. First and second year's growth of houndstongue were harvested from emergence to maturity. Nuclear magnetic resonance was used to determine the levels of total PAs, free base, and N-oxide forms of the alkaloids in leaves, stems, buds, flowers, and pods. PA levels generally were highest (1.5 to 2.0% dry weight) in immature plant tissue, with a gradual decline during maturation. Most plant parts contained greater quantities of the N-oxide form of PAs (60-90%) compared to the free base form. Leaves and pods of mature houndstongue contained sufficient PAs to be potentially toxic if ingested by livestock. This material was digitized as part of a cooperative project between the Society for Range Management and the University of Arizona Libraries. The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact lbry-journals@email.arizona.edu for further information. Migrated from OJS platform August 2020
Scholarly peer-reviewed articles published by the Society for Range Management. Access articles on a rolling-window basis from vol. 1, 1948 up to 5 years from the current year. Formerly Journal of Range Management (JRM). More recent content is available by subscription from SRM.