Yes, Poinciana is toxic to dogs!
Dogs accidentally consuming the Poinciana 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).
Poinciana consumption is also toxic to Cats and Horses.
Toxic Principles Of Poinciana: GI irritants.
More Info About The Poinciana Plant
Scientific Name: Caesalpinia gilliessi
Family: Leguminosae.
Also known as: Peacock Flower, Bird of Paradise, Barbados Pride, Pride of Barbados.
The answer is based on information found on The American Society for the Prevention of Cruelty to Animals (ASPCA) website.