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From: Los Angeles, CA
Region: California
Topic: Poisonous Plants, Trees
Title: Is Lemon Cypress toxic?
Answered by: Nan Hampton
Lemon cypress is a cultivar of Cupressus macrocarpa (Monterey cypress), a native of California. It does not appear on any of the following toxic plant databases:
Poisonous Plants of North Carolina
Cornell University's Plants Poisonous to Livestock and Other Animals
Canadian Poisonous Plants Information System
University of Pennsylvania's Poisonous Plants
California Poison Control System
However, I did find some reports saying the Cupressus macrocarpa caused spontaneous abortions in cattle in New Zealand. The FDA Poisonous Plant Database has a report of poisoning of cattle in New Zealand and in Australia:
MacDonald, J. (1956) Macrocarpa poisoning. New Zealand Veterinary Journal 4:30.
Sloss, V. and J. W. Brady (1983). Abnormal births in cattle following ingestion of Cupressus macrocarpa foliage. Australian Veterinary Journal 60 (7):223.
USDA ARS Poisonous Plant Research database reports a paper stating that the consumption by cattle of Monterey cypress causes abortions. [Lee, S. T. et al. (2003) Development of Enzyme-Linked Immunosorbent Assays for Isocupressic Acid and Serum Metabolites of Isocupresssic Acid. Journal of Agricultural and Food Chemistry.]
It does appear that Cupressus macrocarpa, if eaten, poses a threat to pregnant cattle; but I could find no indication that it is toxic to humans. It would seem prudent, however, NOT to consume it.
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