I was surprised to find out that the very common Sago palm (Cica Revolta) is deadly poisonous to pets and people. The plant contains traces of cyanide that are particularly concentrated in the seeds. So if your pet dropped dead one day and you dont know why check if they had munched on a cycad. They are very common and most gardens in SD and the tourists towns have them.
see
snopes.com: Sago Palm Dangerous to Pets
see
snopes.com: Sago Palm Dangerous to Pets