Yes, Moss Rose is toxic to dogs!
Dogs accidentally consuming the Moss Rose 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).
Moss Rose consumption is also toxic to Cats and Horses.
Toxic Principles Of Moss Rose: Soluble calcium oxalates.
More Info About The Moss Rose Plant
Scientific Name: Portulaca oleracea
Family: Portulacaceae.
Also known as: Wild Portulaca, Rock Moss, Purslane, Pigwee, Pusley.
The answer is based on information found on The American Society for the Prevention of Cruelty to Animals (ASPCA) website.