Yes, Starch Root is toxic to dogs!
Dogs accidentally consuming the Starch Root 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).
Starch Root consumption is also toxic to Cats and Horses.
Toxic Principles Of Starch Root: Insoluble calcium oxalates.
More Info About The Starch Root Plant
Scientific Name: Arum maculatum
Family: Araceae.
Also known as: Arum, Lord-and-Ladies, Adam-and-Eve, Wake Robin, Bobbins, Cuckoo Plant.
The answer is based on information found on The American Society for the Prevention of Cruelty to Animals (ASPCA) website.