Yes, Fern Palm is toxic to dogs!
Dogs accidentally consuming the Fern Palm plants can show the following clinical symptoms: Vomiting, Prolonged Depression, Incoordination, Hypersalivaton, Sleepiness Or Excitation, Dilated Pupils, Low Body Temperature, Low Blood Pressure, Coma, Seizure And Death (In Rare Cases).
Fern Palm consumption is also toxic to Cats and Horses.
Toxic Principles Of Fern Palm: Cycasin, B-methylamino-l-alanine, unidentified neurotoxin (cattle).
More Info About The Fern Palm Plant
Scientific Name: Zamia spp.
Family: Cycadaceae.
Also known as: Sago Palm, Cycads.
The answer is based on information found on The American Society for the Prevention of Cruelty to Animals (ASPCA) website.